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3579 lines
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ReStructuredText
3579 lines
139 KiB
ReStructuredText
.. NOTES
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See "HOW TO ADD A COMMAND-LINE ARGUMENT" in README-maintainer.
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This file contains text that is used for help file generation.
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Lines that start with the magic comment ".. help topic x: y"
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||
introduce a help topic called "x" with short text "y". The contents
|
||
of the comment are the long text.
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||
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The ".. qpdf:option:: option" directive introduces a command-line
|
||
option. The next ".. help: short_text" comment's contents are the
|
||
long text of the help. Search for ".. help-topic" and "qpdf:option"
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||
for additional help. Command line arguments can be referenced using
|
||
:qpdf:ref:`--option`. They also appear in an index.
|
||
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Note: 2022-01-22: because short help text is used in the "schema"
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||
JSON object for QPDFJob JSON, we can't end short text with a ``)``
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character since doing so would cause ``)"`` to appear in the string
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||
literal. We use the R"(...)" syntax for these literals, and that
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||
looks like an end delimiter. While the C++ spec allows
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||
R"anything(...)anything" specifically for this purpose, the MSVC in
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CI at the time of this writing did not support that construct.
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STYLE NOTES
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In this text, :samp:`...` and ``...`` are used somewhat
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interchangeably. :samp: should be used when there is replaceable
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||
text enclosed in curly braces. Otherwise, either is fine. Ideally
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||
there should be a stricter editorial convention, but they render
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||
the same, so I have not gone to the trouble of making it
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consistent.
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||
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USE :qpdf:ref:`--option` to refer to an option whenever it is
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||
specified without parameters in any place other than its own help.
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This creates a link.
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When referring to command-line options, use the following
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||
terminology:
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argument: any command-line argument whether option or positional
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||
option: any argument starting with -- including its parameter, if any
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flag: the --flag part of the option; only use to disambiguate
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parameter: the parameter part of the option
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||
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Example: qpdf in.pdf --object-stream=generalized out.pdf
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Each word is an argument.
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The "--object-stream=generalized" option consists of
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the "--object-stream" flag with the "generalized" parameter. It
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would be okay to talk about "the --object-stream option" in the
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text if there's no ambiguity.
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.. _using:
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Running qpdf
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============
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This chapter describes how to run the qpdf program from the command
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line.
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.. _invocation:
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Basic Invocation
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----------------
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.. help-topic usage: basic invocation
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Read a PDF file, apply transformations or modifications, and write
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a new PDF file.
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Usage: qpdf [infile] [options] [outfile]
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OR qpdf --help[={topic|--option}]
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- infile, options, and outfile may be in any order as long as infile
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precedes outfile.
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- Use --empty in place of an input file for a zero-page, empty input
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- Use --replace-input in place of an output file to overwrite the
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input file with the output
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- outfile may be - to write to stdout; reading from stdin is not supported
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- @filename is an argument file; each line is treated as a separate
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||
command-line argument
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- @- may be used to read arguments from stdin
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- Later options may override earlier options if contradictory
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::
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Usage: qpdf [infile] [options] [outfile]
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The :command:`qpdf` command reads the PDF file :samp:`{infile}`,
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applies various transformations or modifications to the file in
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memory, and writes the result to :samp:`{outfile}`. When run with no
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options, the output file is functionally identical to the input file
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but may be structurally reorganized, and orphaned objects are removed
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from the file. Many options are available for applying transformations
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||
or modifications to the file.
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:samp:`{infile}` can be a regular file, or it can be
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:qpdf:ref:`--empty` to start with an empty PDF file. There is no way
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||
to use standard input since the input file has to be seekable.
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:samp:`{outfile}` can be a regular file, ``-`` to represent standard
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||
output, or :qpdf:ref:`--replace-input` to indicate that the input file
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||
should be overwritten. The output file does not have to be seekable,
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even when generating linearized files. You can also use
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:qpdf:ref:`--split-pages` to create separate output files for each
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page (or group of pages) instead of a single output file.
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||
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||
Password-protected files may be opened by specifying a password with
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:qpdf:ref:`--password`.
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All options other than help options (see :ref:`help-options`) require
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||
an input file. If inspection or JSON options (see
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:ref:`inspection-options` and :ref:`json-options`) or help options are
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||
given, an output file must not be given. Otherwise, an output file is
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||
required.
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||
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||
If :samp:`@filename` appears as a word anywhere in the command-line,
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||
it will be read line by line, and each line will be treated as a
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||
command-line argument. Leading and trailing whitespace is
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||
intentionally not removed from lines, which makes it possible to
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||
handle arguments that start or end with spaces. The :samp:`@-` option
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||
allows arguments to be read from standard input. This allows qpdf to
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||
be invoked with an arbitrary number of arbitrarily long arguments. It
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||
is also very useful for avoiding having to pass passwords on the
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||
command line, though see also :qpdf:ref:`--password-file`. Note that
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||
the :samp:`@filename` can't appear in the middle of an argument, so
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||
constructs such as :samp:`--arg=@filename` will not work. Instead, you
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||
would have to include the option and its parameter (e.g.,
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||
:samp:`--option=parameter`) as a line in the :file:`filename` file and
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just pass :samp:`@filename` on the command line.
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||
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Related Options
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||
~~~~~~~~~~~~~~~
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||
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.. qpdf:option:: --empty
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.. help: use empty file as input
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Use in place of infile for an empty input. Especially useful
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with --pages.
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This option may be given in place of :samp:`{infile}`. This causes
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||
qpdf to use a dummy input file that contains zero pages. This
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||
option is useful in conjunction with :qpdf:ref:`--pages`. See
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:ref:`page-selection` for details.
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||
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.. qpdf:option:: --replace-input
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.. help: overwrite input with output
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Use in place of outfile to overwrite the input file with the output.
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This option may be given in place of :samp:`{outfile}`. This causes
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qpdf to replace the input file with the output. It does this by
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writing to :file:`{infilename}.~qpdf-temp#` and, when done,
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overwriting the input file with the temporary file. If there were
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any warnings, the original input is saved as
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:file:`{infilename}.~qpdf-orig`. If there are errors, the input
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file is left untouched.
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.. qpdf:option:: --job-json-file=file
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.. help: job JSON file
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Specify the name of a file whose contents are expected to
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contain a QPDFJob JSON file. Run qpdf --job-json-help for a
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||
description of the JSON input file format.
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Specify the name of a file whose contents are expected to contain a
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QPDFJob JSON file. This file is read and treated as if the
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equivalent command-line arguments were supplied. It can be repeated
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and mixed freely with other options. Run ``qpdf`` with
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:qpdf:ref:`--job-json-help` for a description of the job JSON input
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file format. For more information, see :ref:`qpdf-job`. Note that
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this is unrelated to :qpdf:ref:`--json` but may be combined with
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it.
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.. _exit-status:
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Exit Status
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-----------
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.. help-topic exit-status: meanings of qpdf's exit codes
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Meaning of exit codes:
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0: no errors or warnings
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1: not used by qpdf but may be used by the shell if unable to invoke qpdf
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2: errors detected
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3: warnings detected, unless --warning-exit-0 is given
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The exit status of :command:`qpdf` may be interpreted as follows:
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.. list-table:: Exit Codes
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:widths: 5 80
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:header-rows: 0
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- - 0
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- no errors or warnings were found
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- - 1
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- not used
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- - 2
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- errors were found; the file was not processed
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- - 3
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- warnings were found without errors
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Notes:
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- A PDF file may have problems that qpdf can't detect.
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- With the :qpdf:ref:`--warning-exit-0` option, exit status ``0`` is
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used even if there are warnings.
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- :command:`qpdf` does not exit with status ``1`` since the shell uses
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this exit code if it is unable to invoke the command.
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- If both errors and warnings were found, exit status ``2`` is used.
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- The :qpdf:ref:`--is-encrypted` and :qpdf:ref:`--requires-password`
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options use different exit codes. See their help for details.
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Related Options
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~~~~~~~~~~~~~~~
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.. qpdf:option:: --warning-exit-0
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.. help: exit 0 even with warnings
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Use exit status 0 instead of 3 when warnings are present. When
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combined with --no-warn, warnings are completely ignored.
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If there were warnings only and no errors, exit with exit code
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``0`` instead of ``3``. When combined with :qpdf:ref:`--no-warn`,
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the effect is for :command:`qpdf` to completely ignore warnings.
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.. _shell-completion:
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Shell Completion
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----------------
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.. help-topic completion: shell completion
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Shell completion is supported with bash and zsh. Use
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eval $(qpdf --completion-bash) or eval $(qpdf --completion-zsh)
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to enable. The QPDF_EXECUTABLE environment variable overrides the
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||
path to qpdf that these commands output.
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:command:`qpdf` provides its own completion support for zsh and bash.
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||
You can enable bash completion with :command:`eval $(qpdf
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--completion-bash)` and zsh completion with :command:`eval $(qpdf
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||
--completion-zsh)`. If :command:`qpdf` is not in your path, you should
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||
use an absolute path to qpdf in the above invocation. If you invoke it
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||
with a relative path, it will warn you, and the completion won't work
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||
if you're in a different directory.
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||
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:command:`qpdf` will use ``argv[0]`` to figure out where its
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||
executable is. This may produce unwanted results in some cases,
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||
especially if you are trying to use completion with a copy of qpdf that
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||
is run directly out of the source tree or that is invoked with a
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||
wrapper script. You can specify a full path to the qpdf you want to
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use for completion in the ``QPDF_EXECUTABLE`` environment variable.
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||
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||
Related Options
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||
~~~~~~~~~~~~~~~
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||
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||
.. qpdf:option:: --completion-bash
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.. help: enable bash completion
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Output a command that enables bash completion
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Output a completion command you can eval to enable shell completion
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from bash.
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||
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.. qpdf:option:: --completion-zsh
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.. help: enable zsh completion
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Output a command that enables zsh completion
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||
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Output a completion command you can eval to enable shell completion
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from zsh.
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||
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.. _help-options:
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||
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Help/Information
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----------------
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||
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.. help-topic help: information about qpdf
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||
Help options provide some information about qpdf itself. Help
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||
options are only valid as the first and only command-line argument.
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||
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||
Help options provide some information about qpdf itself. Help options
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||
are only valid as the first and only command-line argument.
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||
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||
Related Options
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||
~~~~~~~~~~~~~~~
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||
.. qpdf:option:: --help[=--option|topic]
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||
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.. help: provide help
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||
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--help: provide general information and a list of topics
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--help=--option: provide help on a specific option
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--help=topic: provide help on a topic
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||
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||
Display command-line invocation help. Use :samp:`--help={--option}`
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||
for help on a specific option and :samp:`--help={topic}` for help
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||
on a help topic and also provides a list of available help topics.
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||
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||
.. qpdf:option:: --version
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.. help: show qpdf version
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||
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Display the version of qpdf.
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||
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||
Display the version of qpdf. The version number displayed is the
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||
one that is compiled into the qpdf library. If you don't see the
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||
version number you expect, you may have more than one version of
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||
:command:`qpdf` installed and may not have your library path set up
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||
correctly.
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||
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||
.. qpdf:option:: --copyright
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||
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||
.. help: show copyright information
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||
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||
Display copyright and license information.
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||
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||
Display copyright and license information.
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||
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||
.. qpdf:option:: --show-crypto
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||
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.. help: show available crypto providers
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||
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Show a list of available crypto providers, one per line. The
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default provider is shown first.
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||
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||
Show a list of available crypto providers, each on a line by
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||
itself. The default provider is always listed first. See
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:ref:`crypto` for more information about crypto providers.
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||
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||
.. qpdf:option:: --job-json-help
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||
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||
.. help: show format of job JSON
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||
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||
Describe the format of the QPDFJob JSON input used by
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||
--job-json-file.
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||
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||
Describe the format of the QPDFJob JSON input used by
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||
:qpdf:ref:`--job-json-file`. For more information about QPDFJob,
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||
see :ref:`qpdf-job`.
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||
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.. _general-options:
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||
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General Options
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||
---------------
|
||
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.. help-topic general: general options
|
||
|
||
General options control qpdf's behavior in ways that are not
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||
directly related to the operation it is performing.
|
||
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||
This section describes general options that control :command:`qpdf`'s
|
||
behavior. They are not necessarily related to the specific operation
|
||
that is being performed and may be used whether or not an output file
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||
is being created.
|
||
|
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Related Options
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||
~~~~~~~~~~~~~~~
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.. qpdf:option:: --password=password
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||
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.. help: password for encrypted file
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||
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Specify a password for an encrypted, password-protected file.
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||
Not needed for encrypted files without a password.
|
||
|
||
Specifies a password for accessing encrypted, password-protected
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||
files. To read the password from a file or standard input, you can
|
||
use :qpdf:ref:`--password-file`.
|
||
|
||
Prior to 8.4.0, in the case of passwords that contain characters
|
||
that fall outside of 7-bit US-ASCII, qpdf left the burden of
|
||
supplying properly encoded encryption and decryption passwords to
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||
the user. Starting in qpdf 8.4.0, qpdf does this automatically in
|
||
most cases. For an in-depth discussion, please see
|
||
:ref:`unicode-passwords`. Previous versions of this manual
|
||
described workarounds using the :command:`iconv` command. Such
|
||
workarounds are no longer required or recommended starting with
|
||
qpdf 8.4.0. However, for backward compatibility, qpdf attempts to
|
||
detect those workarounds and do the right thing in most cases.
|
||
|
||
.. qpdf:option:: --password-file=filename
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||
|
||
.. help: read password from a file
|
||
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||
The first line of the specified file is used as the password.
|
||
This is used in place of the --password option.
|
||
|
||
Reads the first line from the specified file and uses it as the
|
||
password for accessing encrypted files. :samp:`{filename}` may be
|
||
``-`` to read the password from standard input, but if you do that
|
||
the password is echoed and there is no prompt, so use ``-`` with
|
||
caution. Note that leading and trailing spaces are not stripped
|
||
from the password.
|
||
|
||
.. qpdf:option:: --verbose
|
||
|
||
.. help: print additional information
|
||
|
||
Output additional information about various things qpdf is
|
||
doing, including information about files created and operations
|
||
performed.
|
||
|
||
Increase verbosity of output. This includes information about files
|
||
created, image optimization, and several other operations. In some
|
||
cases, it also displays additional information when inspection
|
||
options (see :ref:`inspection-options`) are used.
|
||
|
||
.. qpdf:option:: --progress
|
||
|
||
.. help: show progress when writing
|
||
|
||
Indicate progress when writing files.
|
||
|
||
Indicate progress while writing output files. Progress indication
|
||
does not start until writing starts, so there may be a delay before
|
||
progress indicators are seen if complicated transformations are
|
||
being applied before the write process begins.
|
||
|
||
.. qpdf:option:: --no-warn
|
||
|
||
.. help: suppress printing of warning messages
|
||
|
||
Suppress printing of warning messages. If warnings were
|
||
encountered, qpdf still exits with exit status 3.
|
||
Use --warning-exit-0 with --no-warn to completely ignore
|
||
warnings.
|
||
|
||
Suppress writing of warnings to stderr. If warnings were detected
|
||
and suppressed, :command:`qpdf` will still exit with exit code 3.
|
||
To completely ignore warnings, also specify
|
||
:qpdf:ref:`--warning-exit-0`. Use with caution as qpdf is not
|
||
always successful in recovering from situations that cause warnings
|
||
to be issued.
|
||
|
||
.. qpdf:option:: --deterministic-id
|
||
|
||
.. help: generate ID deterministically
|
||
|
||
Generate a secure, random document ID only using static
|
||
information, such as the page contents. Does not use the file's
|
||
name or attributes or the current time.
|
||
|
||
Generate a secure, random document ID using deterministic values.
|
||
This prevents use of timestamp and output file name information in
|
||
the ID generation. Instead, at some slight additional runtime cost,
|
||
the ID field is generated to include a digest of the significant
|
||
parts of the content of the output PDF file. This means that a
|
||
given qpdf operation should generate the same ID each time it is
|
||
run, which can be useful when caching results or for generation of
|
||
some test data. Use of this flag is not compatible with creation of
|
||
encrypted files. This option can be useful for testing. See also
|
||
:qpdf:ref:`--static-id`.
|
||
|
||
While qpdf will generate the same deterministic ID given the same
|
||
output PDF, there is no guarantee that different versions of qpdf
|
||
will generate exactly the same PDF output for the same input and
|
||
options. While care is taken to avoid gratuitous changes to qpdf's
|
||
PDF generation, new versions of qpdf may include changes or bug
|
||
fixes that cause slightly different PDF code to be generated. Such
|
||
changes are noted in the release notes.
|
||
|
||
.. qpdf:option:: --allow-weak-crypto
|
||
|
||
.. help: allow insecure cryptographic algorithms
|
||
|
||
Allow creation of files with weak cryptographic algorithms. This
|
||
option is necessary to create 40-bit files or 128-bit files that
|
||
use RC4 encryption.
|
||
|
||
Encrypted PDF files using 40-bit keys or 128-bit keys without AES
|
||
use the insecure *RC4* encryption algorithm. Starting with version
|
||
11.0, qpdf's default behavior is to refuse to write files using RC4
|
||
encryption. Use this option to allow creation of such files. In
|
||
versions 10.4 through 10.6, attempting to create weak encrypted
|
||
files was a warning, rather than an error, without this flag. See
|
||
:ref:`weak-crypto` for additional details.
|
||
|
||
No check is performed for weak crypto when preserving encryption
|
||
parameters from or copying encryption parameters from other files.
|
||
The rationale for this is discussed in :ref:`weak-crypto`.
|
||
|
||
.. qpdf:option:: --keep-files-open=[y|n]
|
||
|
||
.. help: manage keeping multiple files open
|
||
|
||
When qpdf needs to work with many files, as when merging large
|
||
numbers of files, explicitly indicate whether files should be
|
||
kept open. The default behavior is to determine this based on
|
||
the number of files.
|
||
|
||
This option controls whether qpdf keeps individual files open while
|
||
merging. By default, qpdf keeps files open when merging unless more
|
||
than 200 files are specified, in which case files are opened as
|
||
needed and closed when finished. Repeatedly opening
|
||
and closing files may impose a large performance penalty with some
|
||
file systems, especially networked file systems. If you know that
|
||
you have a large enough open file limit and are suffering from
|
||
performance problems, or if you have an open file limit smaller
|
||
than 200, you can use this option to override the default behavior
|
||
by specifying :samp:`--keep-files-open=y` to force :command:`qpdf`
|
||
to keep files open or :samp:`--keep-files-open=n` to force it to
|
||
only open files as needed. See also
|
||
:qpdf:ref:`--keep-files-open-threshold`.
|
||
|
||
Historical note: prior to version 8.1.0, qpdf always kept all files
|
||
open, but this meant that the number of files that could be merged
|
||
was limited by the operating system's open file limit. Version
|
||
8.1.0 opened files as they were referenced and closed them after
|
||
each read, but this caused a major performance impact. Version
|
||
8.2.0 optimized the performance but did so in a way that, for local
|
||
file systems, there was a small but unavoidable performance hit,
|
||
but for networked file systems the performance impact could be
|
||
very high. The current behavior was introduced in qpdf version
|
||
8.2.1.
|
||
|
||
.. qpdf:option:: --keep-files-open-threshold=count
|
||
|
||
.. help: set threshold for --keep-files-open
|
||
|
||
Set the threshold used by --keep-files-open, overriding the
|
||
default value of 200.
|
||
|
||
If specified, overrides the default value of 200 used as the
|
||
threshold for qpdf deciding whether or not to keep files open. See
|
||
:qpdf:ref:`--keep-files-open` for details.
|
||
|
||
.. _advanced-control-options:
|
||
|
||
Advanced Control Options
|
||
------------------------
|
||
|
||
.. help-topic advanced-control: tweak qpdf's behavior
|
||
|
||
Advanced control options control qpdf's behavior in ways that would
|
||
normally never be needed by a user but that may be useful to
|
||
developers or people investigating problems with specific files.
|
||
|
||
Advanced control options control qpdf's behavior in ways that would
|
||
normally never be needed by a user but that may be useful to
|
||
developers or people investigating problems with specific files.
|
||
|
||
Related Options
|
||
~~~~~~~~~~~~~~~
|
||
|
||
.. qpdf:option:: --password-is-hex-key
|
||
|
||
.. help: provide hex-encoded encryption key
|
||
|
||
Provide the underlying file encryption key as a hex-encoded
|
||
string rather than supplying a password. This is an expert
|
||
option.
|
||
|
||
Overrides the usual computation/retrieval of the PDF file's
|
||
encryption key from user/owner password with an explicit
|
||
specification of the encryption key. When this option is specified,
|
||
the parameter to the :qpdf:ref:`--password` option is interpreted as
|
||
a hexadecimal-encoded key value. This only applies to the password
|
||
used to open the main input file. It does not apply to other files
|
||
opened by :qpdf:ref:`--pages` or other options or to files being
|
||
written.
|
||
|
||
Most users will never have a need for this option, and no standard
|
||
viewers support this mode of operation, but it can be useful for
|
||
forensic or investigatory purposes. For example, if a PDF file is
|
||
encrypted with an unknown password, a brute-force attack using the
|
||
key directly is sometimes more efficient than one using the
|
||
password. Also, if a file is heavily damaged, it may be possible to
|
||
derive the encryption key and recover parts of the file using it
|
||
directly. To expose the encryption key used by an encrypted file
|
||
that you can open normally, use the
|
||
:qpdf:ref:`--show-encryption-key` option.
|
||
|
||
.. qpdf:option:: --suppress-password-recovery
|
||
|
||
.. help: don't try different password encodings
|
||
|
||
Suppress qpdf's usual behavior of attempting different encodings
|
||
of a password that contains non-ASCII Unicode characters if the
|
||
first attempt doesn't succeed.
|
||
|
||
Ordinarily, qpdf attempts to automatically compensate for passwords
|
||
encoded with the wrong character encoding. This option suppresses
|
||
that behavior. Under normal conditions, there are no reasons to use
|
||
this option. See :ref:`unicode-passwords` for a discussion.
|
||
|
||
.. qpdf:option:: --password-mode=mode
|
||
|
||
.. help: tweak how qpdf encodes passwords
|
||
|
||
Fine-tune how qpdf controls encoding of Unicode passwords. Valid
|
||
options are auto, bytes, hex-bytes, and unicode.
|
||
|
||
This option can be used to fine-tune how qpdf interprets Unicode
|
||
(non-ASCII) password strings passed on the command line. With the
|
||
exception of the :samp:`hex-bytes` mode, these only apply to
|
||
passwords provided when encrypting files. The :samp:`hex-bytes`
|
||
mode also applies to passwords specified for reading files. For
|
||
additional discussion of the supported password modes and when you
|
||
might want to use them, see :ref:`unicode-passwords`. The following
|
||
modes are supported:
|
||
|
||
- :samp:`auto`: Automatically determine whether the specified
|
||
password is a properly encoded Unicode (UTF-8) string, and
|
||
transcode it as required by the PDF spec based on the type of
|
||
encryption being applied. On Windows starting with version 8.4.0,
|
||
and on almost all other modern platforms, incoming passwords will
|
||
be properly encoded in UTF-8, so this is almost always what you
|
||
want.
|
||
|
||
- :samp:`unicode`: Tells qpdf that the incoming password is UTF-8,
|
||
overriding whatever its automatic detection determines. The only
|
||
difference between this mode and :samp:`auto` is that qpdf will
|
||
fail with an error message if the password is not valid UTF-8
|
||
instead of falling back to :samp:`bytes` mode with a warning.
|
||
|
||
- :samp:`bytes`: Interpret the password as a literal byte string.
|
||
For non-Windows platforms, this is what versions of qpdf prior to
|
||
8.4.0 did. For Windows platforms, there is no way to specify
|
||
strings of binary data on the command line directly, but you can
|
||
use a :samp:`@filename` option or :qpdf:ref:`--password-file` to
|
||
do it, in which case this option forces qpdf to respect the
|
||
string of bytes as provided. Note that this option may cause you
|
||
to encrypt PDF files with passwords that will not be usable by
|
||
other readers.
|
||
|
||
- :samp:`hex-bytes`: Interpret the password as a hex-encoded
|
||
string. This provides a way to pass binary data as a password on
|
||
all platforms including Windows. As with :samp:`bytes`, this
|
||
option may allow creation of files that can't be opened by other
|
||
readers. This mode affects qpdf's interpretation of passwords
|
||
specified for decrypting files as well as for encrypting them. It
|
||
makes it possible to specify strings that are encoded in some
|
||
manner other than the system's default encoding.
|
||
|
||
.. qpdf:option:: --suppress-recovery
|
||
|
||
.. help: suppress error recovery
|
||
|
||
Avoid attempting to recover when errors are found in a file's
|
||
cross reference table or stream lengths.
|
||
|
||
Prevents qpdf from attempting to reconstruct a file's cross
|
||
reference table when there are errors reading objects from the
|
||
file. Recovery is triggered by a variety of situations. While
|
||
usually successful, it uses heuristics that don't work on all
|
||
files. If this option is given, :command:`qpdf` fails on the first
|
||
error it encounters.
|
||
|
||
.. qpdf:option:: --ignore-xref-streams
|
||
|
||
.. help: use xref tables rather than streams
|
||
|
||
Ignore any cross-reference streams in the file, falling back to
|
||
cross-reference tables or triggering document recovery.
|
||
|
||
Tells qpdf to ignore any cross-reference streams, falling back to
|
||
any embedded cross-reference tables or triggering document
|
||
recovery. Ordinarily, qpdf reads cross-reference streams when they
|
||
are present in a PDF file. If this option is specified,
|
||
qpdf will ignore any cross-reference streams for hybrid PDF files.
|
||
The purpose of hybrid files is to make some content available to
|
||
viewers that are not aware of cross-reference streams. It is almost
|
||
never desirable to ignore them. The only time when you might want
|
||
to use this feature is if you are testing creation of hybrid PDF
|
||
files and wish to see how a PDF consumer that doesn't understand
|
||
object and cross-reference streams would interpret such a file.
|
||
|
||
.. _transformation-options:
|
||
|
||
PDF Transformation
|
||
------------------
|
||
|
||
.. help-topic transformation: make structural PDF changes
|
||
|
||
The options below tell qpdf to apply transformations that change
|
||
the structure without changing the content.
|
||
|
||
The options discussed in this section tell qpdf to apply
|
||
transformations that change the structure of a PDF file without
|
||
changing its content. Examples include creating linearized
|
||
(web-optimized) files, adding or removing encryption, restructuring
|
||
files for older viewers, and rewriting files for human inspection. See
|
||
also :ref:`modification-options`.
|
||
|
||
Related Options
|
||
~~~~~~~~~~~~~~~
|
||
|
||
.. qpdf:option:: --linearize
|
||
|
||
.. help: linearize (web-optimize) output
|
||
|
||
Create linearized (web-optimized) output files.
|
||
|
||
Create linearized (web-optimized) output files. Linearized files
|
||
are formatted in a way that allows compliant readers to begin
|
||
displaying a PDF file before it is fully downloaded. Ordinarily,
|
||
the entire file must be present before it can be rendered because
|
||
important cross-reference information typically appears at the end
|
||
of the file.
|
||
|
||
.. qpdf:option:: --encrypt user-password owner-password key-length [options] --
|
||
|
||
.. help: start encryption options
|
||
|
||
Run qpdf --help=encryption for details.
|
||
|
||
This flag starts encryption options, used to create encrypted
|
||
files. Please see :ref:`encryption-options` for details.
|
||
|
||
.. qpdf:option:: --decrypt
|
||
|
||
.. help: remove encryption from input file
|
||
|
||
Create an unencrypted output file even if the input file was
|
||
encrypted. Normally qpdf preserves whatever encryption was
|
||
present on the input file. This option overrides that behavior.
|
||
|
||
Create an output file with no encryption even if the input file is
|
||
encrypted. This option overrides the default behavior of preserving
|
||
whatever encryption was present on the input file. This
|
||
functionality is not intended to be used for bypassing copyright
|
||
restrictions or other restrictions placed on files by their
|
||
producers. See also :qpdf:ref:`--copy-encryption`.
|
||
|
||
.. qpdf:option:: --copy-encryption=file
|
||
|
||
.. help: copy another file's encryption details
|
||
|
||
Copy encryption details from the specified file instead of
|
||
preserving the input file's encryption. Use --encryption-file-password
|
||
to specify the encryption file's password.
|
||
|
||
Copy all encryption parameters, including the user password, the
|
||
owner password, and all security restrictions, from the specified
|
||
file instead of preserving the encryption details from the input
|
||
file. This works even if only one of the user password or owner
|
||
password is known. If the encryption file requires a password, use
|
||
the :qpdf:ref:`--encryption-file-password` option to set it. Note
|
||
that copying the encryption parameters from a file also copies the
|
||
first half of ``/ID`` from the file since this is part of the
|
||
encryption parameters. This option can be useful if you need to
|
||
decrypt a file to make manual changes to it or to change it outside
|
||
of qpdf, and then want to restore the original encryption on the
|
||
file without having to manual specify all the individual settings.
|
||
See also :qpdf:ref:`--decrypt`.
|
||
|
||
Checks for weak cryptographic algorithms are intentionally not made
|
||
by this operation. See :ref:`weak-crypto` for the rationale.
|
||
|
||
.. qpdf:option:: --encryption-file-password=password
|
||
|
||
.. help: supply password for --copy-encryption
|
||
|
||
If the file named in --copy-encryption requires a password, use
|
||
this option to supply the password.
|
||
|
||
If the file specified with :qpdf:ref:`--copy-encryption`
|
||
requires a password, supply the password using this option. This
|
||
option is necessary because the :qpdf:ref:`--password` option
|
||
applies to the input file, not the file from which encryption is
|
||
being copied.
|
||
|
||
.. qpdf:option:: --qdf
|
||
|
||
.. help: enable viewing PDF code in a text editor
|
||
|
||
Create a PDF file suitable for viewing in a text editor and even
|
||
editing. This is for editing the PDF code, not the page contents.
|
||
All streams that can be uncompressed are uncompressed, and
|
||
content streams are normalized, among other changes. The
|
||
companion tool "fix-qdf" can be used to repair hand-edited QDF
|
||
files. QDF is a feature specific to the qpdf tool. Please see
|
||
the "QDF Mode" chapter in the manual.
|
||
|
||
Create a PDF file suitable for viewing and editing in a text
|
||
editor. This is to edit the PDF code, not the page contents. To
|
||
edit a QDF file, your text editor must preserve binary data. In a
|
||
QDF file, all streams that can be uncompressed are uncompressed,
|
||
and content streams are normalized, among other changes. The
|
||
companion tool :command:`fix-qdf` can be used to repair hand-edited
|
||
QDF files. QDF is a feature specific to the qpdf tool. For
|
||
additional information, see :ref:`qdf`. Note that
|
||
:qpdf:ref:`--linearize` disables QDF mode.
|
||
|
||
QDF mode has full support for object streams, but sometimes it's
|
||
easier to locate a specific object if object streams are disabled.
|
||
When trying to understand some PDF construct by inspecting an
|
||
existing file, it can be useful to combine :samp:`--qdf` with
|
||
:samp:`--object-streams=disable`.
|
||
|
||
This flag changes some of the defaults of other options: stream
|
||
data is uncompressed, content streams are normalized, and
|
||
encryption is removed. These defaults can still be overridden by
|
||
specifying the appropriate options with :samp:`--qdf`.
|
||
Additionally, in QDF mode, stream lengths are stored as indirect
|
||
objects, objects are formatted in a less efficient but more
|
||
readable fashion, and the documents are interspersed with comments
|
||
that make it easier for the user to find things and also make it
|
||
possible for :command:`fix-qdf` to work properly. When editing QDF
|
||
files, it is not necessary to maintain the object formatting.
|
||
|
||
When normalizing content, if qpdf runs into any lexical errors, it
|
||
will print a warning indicating that content may be damaged. If you
|
||
want to create QDF files without content normalization, specify
|
||
:samp:`--qdf --normalize-content=n`. You can also create a non-QDF
|
||
file with uncompressed streams using
|
||
:samp:`--stream-data=uncompress`. Either option will uncompress all
|
||
the streams but will not attempt to normalize content. Please note
|
||
that if you are using content normalization or QDF mode for the
|
||
purpose of manually inspecting files, you don't have to care about
|
||
this.
|
||
|
||
See also :qpdf:ref:`--no-original-object-ids`.
|
||
|
||
.. qpdf:option:: --no-original-object-ids
|
||
|
||
.. help: omit original object IDs in qdf
|
||
|
||
Omit comments in a QDF file indicating the object ID an object
|
||
had in the original file.
|
||
|
||
Suppresses inclusion of original object ID comments in QDF files.
|
||
This can be useful when generating QDF files for test purposes,
|
||
particularly when comparing them to determine whether two PDF files
|
||
have identical content. The original object ID comment is there by
|
||
default because it makes it easier to trace objects back to the
|
||
original file.
|
||
|
||
.. qpdf:option:: --compress-streams=[y|n]
|
||
|
||
.. help: compress uncompressed streams
|
||
|
||
Setting --compress-streams=n prevents qpdf from compressing
|
||
uncompressed streams. This can be useful if you are leaving some
|
||
streams uncompressed intentionally.
|
||
|
||
By default, or with :samp:`--compress-streams=y`, qpdf will
|
||
compress streams using the flate compression algorithm (used by zip
|
||
and gzip) unless those streams are compressed in some other way.
|
||
This analysis is made after qpdf attempts to uncompress streams and
|
||
is therefore closely related to :qpdf:ref:`--decode-level`. To
|
||
suppress this behavior and leave streams streams uncompressed, use
|
||
:samp:`--compress-streams=n`. In QDF mode (see :ref:`qdf` and
|
||
:qpdf:ref:`--qdf`), the default is to leave streams uncompressed.
|
||
|
||
.. qpdf:option:: --decode-level=parameter
|
||
|
||
.. help: control which streams to uncompress
|
||
|
||
When uncompressing streams, control which types of compression
|
||
schemes should be uncompressed:
|
||
- none: don't uncompress anything. This is the default with
|
||
--json-output.
|
||
- generalized: uncompress streams compressed with a
|
||
general-purpose compression algorithm. This is the default
|
||
except when --json-output is given.
|
||
- specialized: in addition to generalized, also uncompress
|
||
streams compressed with a special-purpose but non-lossy
|
||
compression scheme
|
||
- all: in addition to specialized, uncompress streams compressed
|
||
with lossy compression schemes like JPEG (DCT)
|
||
qpdf does not know how to uncompress all compression schemes.
|
||
|
||
Controls which streams qpdf tries to decode. The default is
|
||
:samp:`generalized`.
|
||
|
||
The following values for :samp:`{parameter}` are available:
|
||
|
||
- :samp:`none`: do not attempt to decode any streams. This is the
|
||
default with :qpdf:ref:`--json-output`.
|
||
|
||
- :samp:`generalized`: decode streams filtered with supported
|
||
generalized filters: ``/LZWDecode``, ``/FlateDecode``,
|
||
``/ASCII85Decode``, and ``/ASCIIHexDecode``. We define
|
||
generalized filters as those to be used for general-purpose
|
||
compression or encoding, as opposed to filters specifically
|
||
designed for image data. This is the default except when
|
||
:qpdf:ref:`--json-output` is given.
|
||
|
||
- :samp:`specialized`: in addition to generalized, decode streams
|
||
with supported non-lossy specialized filters; currently this is
|
||
just ``/RunLengthDecode``
|
||
|
||
- :samp:`all`: in addition to generalized and specialized, decode
|
||
streams with supported lossy filters; currently this is just
|
||
``/DCTDecode`` (JPEG)
|
||
|
||
There are several filters that :command:`qpdf` does not support.
|
||
These are left untouched regardless of the option. Future versions
|
||
of qpdf may support additional filters.
|
||
|
||
Because the default value is ``generalized``, qpdf's default
|
||
behavior is to uncompress any stream that is encoded using
|
||
non-lossy filters that qpdf understands. If
|
||
``--compress-streams=y`` is also in effect, which is the default
|
||
(see :qpdf:ref:`--compress-streams`), the overall effect is that
|
||
qpdf will recompress streams with generalized filters using flate
|
||
compression, effectively eliminating LZW and ASCII-based filters.
|
||
This is usually desirable behavior but can be disabled with
|
||
``--decode-level=none``. Note that ``--decode-level=none`` is the
|
||
default when :qpdf:ref:`--json-output` is specified, but it can be
|
||
overridden in that case as well.
|
||
|
||
As a special case, streams already compressed with ``/FlateDecode``
|
||
are not uncompressed and recompressed. You can change this behavior
|
||
with :qpdf:ref:`--recompress-flate`.
|
||
|
||
.. qpdf:option:: --stream-data=parameter
|
||
|
||
.. help: control stream compression
|
||
|
||
This option controls how streams are compressed in the output.
|
||
It is less granular than the newer options, --compress-streams
|
||
and --decode-level.
|
||
|
||
Parameters:
|
||
- compress: same as --compress-streams=y --decode-level=generalized
|
||
- preserve: same as --compress-streams=n --decode-level=none
|
||
- uncompress: same as --compress-streams=n --decode-level=generalized
|
||
|
||
Controls transformation of stream data. This option predates the
|
||
:qpdf:ref:`--compress-streams` and :qpdf:ref:`--decode-level`
|
||
options. Those options can be used to achieve the same effect with
|
||
more control. The value of :samp:`{parameter}` may be one of the
|
||
following:
|
||
|
||
- :samp:`compress`: recompress stream data when possible (default);
|
||
equivalent to :samp:`--compress-streams=y`
|
||
:samp:`--decode-level=generalized`. Does not recompress streams
|
||
already compressed with ``/FlateDecode`` unless
|
||
:qpdf:ref:`--recompress-flate` is also specified.
|
||
|
||
- :samp:`preserve`: leave all stream data as is; equivalent to
|
||
:samp:`--compress-streams=n` :samp:`--decode-level=none`
|
||
|
||
- :samp:`uncompress`: uncompress stream data compressed with
|
||
generalized filters when possible; equivalent to
|
||
:samp:`--compress-streams=n` :samp:`--decode-level=generalized`
|
||
|
||
.. qpdf:option:: --recompress-flate
|
||
|
||
.. help: uncompress and recompress flate
|
||
|
||
The default generalized compression scheme used by PDF is flate,
|
||
which is the same as used by zip and gzip. Usually qpdf just
|
||
leaves these alone. This option tells qpdf to uncompress and
|
||
recompress streams compressed with flate. This can be useful
|
||
when combined with --compression-level.
|
||
|
||
The default generalized compression scheme used by PDF is flate
|
||
(``/FlateDecode``), which is the same as used by :command:`zip` and
|
||
:command:`gzip`. Usually qpdf just leaves these alone. This option
|
||
tells :command:`qpdf` to uncompress and recompress streams
|
||
compressed with flate. This can be useful when combined with
|
||
:qpdf:ref:`--compression-level`. Using this option may make
|
||
:command:`qpdf` much slower when writing output files.
|
||
|
||
.. qpdf:option:: --compression-level=level
|
||
|
||
.. help: set compression level for flate
|
||
|
||
Set a compression level from 1 (least, fastest) to 9 (most,
|
||
slowest) when compressing files with flate (used in zip and
|
||
gzip), which is the default compression for most PDF files.
|
||
You need --recompress-flate with this option if you want to
|
||
change already compressed streams.
|
||
|
||
When writing new streams that are compressed with ``/FlateDecode``,
|
||
use the specified compression level. The value of :samp:`level`
|
||
should be a number from 1 to 9 and is passed directly to zlib,
|
||
which implements deflate compression. Lower numbers compress less
|
||
and are faster; higher numbers compress more and are slower. Note
|
||
that :command:`qpdf` doesn't uncompress and recompress streams
|
||
compressed with flate by default. To have this option apply to
|
||
already compressed streams, you should also specify
|
||
:qpdf:ref:`--recompress-flate`. If your goal is to shrink the size
|
||
of PDF files, you should also use
|
||
:samp:`--object-streams=generate`. If you omit this option, qpdf
|
||
defers to the compression library's default behavior.
|
||
|
||
.. qpdf:option:: --normalize-content=[y|n]
|
||
|
||
.. help: fix newlines in content streams
|
||
|
||
Normalize newlines to UNIX-style newlines in PDF content
|
||
streams, which is useful for viewing them in a programmer's text
|
||
editor across multiple platforms. This is also turned on by
|
||
--qdf.
|
||
|
||
Enables or disables normalization of newlines in PDF content
|
||
streams to UNIX-style newlines, which is useful for viewing files
|
||
in a programmer-friendly text edit across multiple platforms.
|
||
Content normalization is off by default, but is automatically
|
||
enabled by :qpdf:ref:`--qdf` (see also :ref:`qdf`). It is not
|
||
recommended to use this option for production use. If qpdf runs
|
||
into any lexical errors while normalizing content, it will print a
|
||
warning indicating that content may be damaged.
|
||
|
||
.. qpdf:option:: --object-streams=mode
|
||
|
||
.. help: control use of object streams
|
||
|
||
Control what qpdf does regarding object streams. Options:
|
||
- preserve: preserve original object streams, if any (the default)
|
||
- disable: create output files with no object streams
|
||
- generate: create object streams, and compress objects when possible
|
||
|
||
Controls handling of object streams. The value of :samp:`{mode}`
|
||
may be one of the following:
|
||
|
||
.. list-table:: Object Stream Modes
|
||
:widths: 10 80
|
||
:header-rows: 0
|
||
|
||
- - :samp:`preserve`
|
||
- preserve original object streams, if any (the default)
|
||
|
||
- - :samp:`disable`
|
||
- create output files with no object streams
|
||
|
||
- - :samp:`generate`
|
||
- create object streams, and compress objects when possible
|
||
|
||
Object streams are PDF streams that contain other objects. Putting
|
||
objects into object streams allows the PDF objects themselves to be
|
||
compressed, which can result in much smaller PDF files. Combining
|
||
this option with :qpdf:ref:`--compression-level` and
|
||
:qpdf:ref:`--recompress-flate` can often result in the creation of
|
||
smaller PDF files.
|
||
|
||
Object streams, also known as compressed objects, were introduced
|
||
into the PDF specification at version 1.5 around 2003. Some ancient
|
||
PDF viewers may not support files with object streams. qpdf can be
|
||
used to transform files with object streams into files without object
|
||
streams or vice versa.
|
||
|
||
In :samp:`preserve` mode, the relationship between objects and the
|
||
streams that contain them is preserved from the original file. If
|
||
the file has no object streams, qpdf will not add any. In
|
||
:samp:`disable` mode, all objects are written as regular,
|
||
uncompressed objects. The resulting file should be structurally
|
||
readable by older PDF viewers, though there is still a chance that
|
||
the file may contain other content that some older readers can't
|
||
support. In :samp:`generate` mode, qpdf will create its own object
|
||
streams. This will usually result in more compact PDF files. In
|
||
this mode, qpdf will also make sure the PDF version number in the
|
||
header is at least 1.5.
|
||
|
||
.. qpdf:option:: --preserve-unreferenced
|
||
|
||
.. help: preserve unreferenced objects
|
||
|
||
Preserve all objects from the input even if not referenced.
|
||
|
||
Tells qpdf to preserve objects that are not referenced when writing
|
||
the file. Ordinarily any object that is not referenced in a
|
||
traversal of the document from the trailer dictionary will be
|
||
discarded. Disabling this default behavior may be useful in working
|
||
with some damaged files or inspecting files with known unreferenced
|
||
objects.
|
||
|
||
This flag is ignored for linearized files and has the effect of
|
||
causing objects in the new file to be written ordered by object ID
|
||
from the original file. This does not mean that object numbers will
|
||
be the same since qpdf may create stream lengths as direct or
|
||
indirect differently from the original file, and the original file
|
||
may have gaps in its numbering.
|
||
|
||
See also :qpdf:ref:`--preserve-unreferenced-resources`, which does
|
||
something completely different.
|
||
|
||
.. qpdf:option:: --remove-unreferenced-resources=parameter
|
||
|
||
.. help: remove unreferenced page resources
|
||
|
||
Remove from a page's resource dictionary any resources that are
|
||
not referenced in the page's contents. Parameters: "auto"
|
||
(default), "yes", "no".
|
||
|
||
Parameters: ``auto`` (the default), ``yes``, or ``no``.
|
||
|
||
Starting with qpdf 8.1, when splitting pages, qpdf is able to
|
||
attempt to remove images and fonts that are not used by a page even
|
||
if they are referenced in the page's resources dictionary. When
|
||
shared resources are in use, this behavior can greatly reduce the
|
||
file sizes of split pages, but the analysis is very slow. In
|
||
versions from 8.1 through 9.1.1, qpdf did this analysis by default.
|
||
Starting in qpdf 10.0.0, if ``auto`` is used, qpdf does a quick
|
||
analysis of the file to determine whether the file is likely to
|
||
have unreferenced objects on pages, a pattern that frequently
|
||
occurs when resource dictionaries are shared across multiple pages
|
||
and rarely occurs otherwise. If it discovers this pattern, then it
|
||
will attempt to remove unreferenced resources. Usually this means
|
||
you get the slower splitting speed only when it's actually going to
|
||
create smaller files. You can suppress removal of unreferenced
|
||
resources altogether by specifying ``no`` or force qpdf to do the
|
||
full algorithm by specifying ``yes``.
|
||
|
||
Other than cases in which you don't care about file size and care a
|
||
lot about runtime, there are few reasons to use this option,
|
||
especially now that ``auto`` mode is supported. One reason to use
|
||
this is if you suspect that qpdf is removing resources it shouldn't
|
||
be removing. If you encounter such a case, please report it as a bug at
|
||
https://github.com/qpdf/qpdf/issues/.
|
||
|
||
.. qpdf:option:: --preserve-unreferenced-resources
|
||
|
||
.. help: use --remove-unreferenced-resources=no
|
||
|
||
Synonym for --remove-unreferenced-resources=no. Use that instead.
|
||
|
||
This is a synonym for :samp:`--remove-unreferenced-resources=no`.
|
||
See :qpdf:ref:`--remove-unreferenced-resources`.
|
||
|
||
See also :qpdf:ref:`--preserve-unreferenced`, which does something
|
||
completely different. To reduce confusion, you should use
|
||
:samp:`--remove-unreferenced-resources=no` instead.
|
||
|
||
.. qpdf:option:: --newline-before-endstream
|
||
|
||
.. help: force a newline before endstream
|
||
|
||
For an extra newline before endstream. Using this option enables
|
||
qpdf to preserve PDF/A when rewriting such files.
|
||
|
||
Tell qpdf to insert a newline before the ``endstream`` keyword,
|
||
not counted in the length, after any stream content even if the
|
||
last character of the stream was a newline. This may result in two
|
||
newlines in some cases. This is a requirement of PDF/A. While qpdf
|
||
doesn't specifically know how to generate PDF/A-compliant PDFs,
|
||
this at least prevents it from removing compliance on already
|
||
compliant files.
|
||
|
||
.. qpdf:option:: --coalesce-contents
|
||
|
||
.. help: combine content streams
|
||
|
||
If a page has an array of content streams, concatenate them into
|
||
a single content stream.
|
||
|
||
When a page's contents are split across multiple streams, this
|
||
option causes qpdf to combine them into a single stream. Use of
|
||
this option is never necessary for ordinary usage, but it can help
|
||
when working with some files in some cases. For example, this can
|
||
be combined with QDF mode or content normalization to make it
|
||
easier to look at all of a page's contents at once. It is common
|
||
for PDF writers to create multiple content streams for a variety of
|
||
reasons such as making it easier to modify page contents and
|
||
splitting very large content streams so PDF viewers may be able to
|
||
use less memory.
|
||
|
||
.. qpdf:option:: --externalize-inline-images
|
||
|
||
.. help: convert inline to regular images
|
||
|
||
Convert inline images to regular images.
|
||
|
||
Convert inline images to regular images. By default, images whose
|
||
data is at least 1,024 bytes are converted when this option is
|
||
selected. Use :qpdf:ref:`--ii-min-bytes` to change the size
|
||
threshold. This option is implicitly selected when
|
||
:qpdf:ref:`--optimize-images` is selected unless
|
||
:qpdf:ref:`--keep-inline-images` is also specified.
|
||
|
||
.. qpdf:option:: --ii-min-bytes=size-in-bytes
|
||
|
||
.. help: set minimum size for --externalize-inline-images
|
||
|
||
Don't externalize inline images smaller than this size. The
|
||
default is 1,024. Use 0 for no minimum.
|
||
|
||
Avoid converting inline images whose size is below the specified
|
||
minimum size to regular images. The default is 1,024 bytes. Use 0
|
||
for no minimum.
|
||
|
||
.. qpdf:option:: --min-version=version
|
||
|
||
.. help: set minimum PDF version
|
||
|
||
Force the PDF version of the output to be at least the specified
|
||
version. The version number format is
|
||
"major.minor[.extension-level]", which sets the version header
|
||
to "major.minor" and the extension level, if specified, to
|
||
"extension-level".
|
||
|
||
Force the PDF version of the output file to be at least
|
||
:samp:`{version}`. In other words, if the input file has a lower
|
||
version than the specified version, the specified version will be
|
||
used. If the input file has a higher version, the input file's
|
||
original version will be used. It is seldom necessary to use this
|
||
option since qpdf will automatically increase the version as needed
|
||
when adding features that require newer PDF readers.
|
||
|
||
The version number may be expressed in the form
|
||
:samp:`{major}.{minor}[.{extension-level}]`. If
|
||
:samp:`.{extension-level}`, is given, version is interpreted as
|
||
:samp:`{major.minor}` at extension level :samp:`{extension-level}`.
|
||
For example, version ``1.7.8`` represents version 1.7 at extension
|
||
level 8. Note that minimal syntax checking is done on the command
|
||
line. :command:`qpdf` does not check whether the specified version
|
||
is actually required.
|
||
|
||
.. qpdf:option:: --force-version=version
|
||
|
||
.. help: set output PDF version
|
||
|
||
Force the output PDF file's PDF version header to be the specified
|
||
value, even if the file uses features that may not be available
|
||
in that version.
|
||
|
||
This option forces the PDF version to be the exact version
|
||
specified *even when the file may have content that is not
|
||
supported in that version*. The version number is interpreted in
|
||
the same way as with :qpdf:ref:`--min-version` so that extension
|
||
levels can be set. In some cases, forcing the output file's PDF
|
||
version to be lower than that of the input file will cause qpdf to
|
||
disable certain features of the document. Specifically, 256-bit
|
||
keys are disabled if the version is less than 1.7 with extension
|
||
level 8 (except the deprecated, unsupported "R5" format is allowed
|
||
with extension levels 3 through 7), AES encryption is disabled if
|
||
the version is less than 1.6, cleartext metadata and object streams
|
||
are disabled if less than 1.5, 128-bit encryption keys are disabled
|
||
if less than 1.4, and all encryption is disabled if less than 1.3.
|
||
Even with these precautions, qpdf won't be able to do things like
|
||
eliminate use of newer image compression schemes, transparency
|
||
groups, or other features that may have been added in more recent
|
||
versions of PDF.
|
||
|
||
As a general rule, with the exception of big structural things like
|
||
the use of object streams or AES encryption, PDF viewers are
|
||
supposed to ignore features they don't support. This means that
|
||
forcing the version to a lower version may make it possible to open
|
||
your PDF file with an older version, though bear in mind that some
|
||
of the original document's functionality may be lost.
|
||
|
||
.. _page-ranges:
|
||
|
||
Page Ranges
|
||
-----------
|
||
|
||
.. help-topic page-ranges: page range syntax
|
||
|
||
A full description of the page range syntax, with examples, can be
|
||
found in the manual. Summary:
|
||
|
||
- a,b,c pages a, b, and c
|
||
- a-b pages a through b inclusive; if a > b, this counts down
|
||
- r<n> where <n> represents a number is the <n>th page from the end
|
||
- z the last page, same as r1
|
||
|
||
You can append :even or :odd to select every other page from the
|
||
resulting set of pages, where :odd starts with the first page and
|
||
:even starts with the second page. These are odd and even pages
|
||
from the resulting set, not based on the original page numbers.
|
||
|
||
Several :command:`qpdf` command-line options use page ranges. This
|
||
section describes the syntax of a page range.
|
||
|
||
- A plain number indicates a page numbered from ``1``, so ``1``
|
||
represents the first page.
|
||
|
||
- A number preceded by ``r`` counts from the end, so ``r1`` is the
|
||
last page, ``r2`` is the second-to-last page, etc.
|
||
|
||
- The letter ``z`` represents the last page and is the same as ``r1``.
|
||
|
||
- Page numbers may appear in any order separated by commas.
|
||
|
||
- Two page numbers separated by dashes represents the inclusive range
|
||
of pages from the first to the second. If the first number is higher
|
||
than the second number, it is the range of pages in reverse.
|
||
|
||
- The range may be appended with ``:odd`` or ``:even`` to select only
|
||
pages from the resulting range in odd or even positions. In this
|
||
case, odd and even refer to positions in the final range, not
|
||
whether the original page number is odd or even.
|
||
|
||
.. list-table:: Example Page Ranges
|
||
:widths: 20 80
|
||
:header-rows: 0
|
||
|
||
- - ``1,6,4``
|
||
- pages 1, 6, and 4 in that order
|
||
|
||
- - ``3-7``
|
||
- pages 3 through 7 inclusive in increasing order
|
||
|
||
- - ``7-3``
|
||
- pages 7, 6, 5, 4, and 3 in that order
|
||
|
||
- - ``1-z``
|
||
- all pages in order
|
||
|
||
- - ``z-1``
|
||
- all pages in reverse order
|
||
|
||
- - ``1,3,5-9,15-12``
|
||
- pages 1, 3, 5, 6, 7, 8, 9, 15, 14, 13, and 12 in that order
|
||
|
||
- - ``r3-r1``
|
||
- the last three pages of the document
|
||
|
||
- - ``r1-r3``
|
||
- the last three pages of the document in reverse order
|
||
|
||
- - ``1-20:even``
|
||
- even pages from 2 to 20
|
||
|
||
- - ``5,7-9,12``
|
||
- pages 5, 7, 8, 9, and 12
|
||
|
||
- - ``5,7-9,12:odd``
|
||
- pages 5, 8, and 12, which are the pages in odd positions from
|
||
the original set of 5, 7, 8, 9, 12
|
||
|
||
- - ``5,7-9,12:even``
|
||
- pages 7 and 9, which are the pages in even positions from the
|
||
original set of 5, 7, 8, 9, 12
|
||
|
||
.. _modification-options:
|
||
|
||
PDF Modification
|
||
----------------
|
||
|
||
.. help-topic modification: change parts of the PDF
|
||
|
||
Modification options make systematic changes to certain parts of
|
||
the PDF, causing the PDF to render differently from the original.
|
||
|
||
Modification options make systematic changes to certain parts of the
|
||
PDF, causing the PDF to render differently from the original. See also
|
||
:ref:`transformation-options`.
|
||
|
||
Related Options
|
||
~~~~~~~~~~~~~~~
|
||
|
||
.. qpdf:option:: --pages file [--password=password] [page-range] [...] --
|
||
|
||
.. help: begin page selection
|
||
|
||
Run qpdf --help=page-selection for details.
|
||
|
||
This flag starts page selection options, which are used to select
|
||
pages from one or more input files to perform operations such as
|
||
splitting, merging, and collating files.
|
||
|
||
Please see :ref:`page-selection` for details about selecting pages.
|
||
|
||
See also :qpdf:ref:`--split-pages`, :qpdf:ref:`--collate`,
|
||
:ref:`page-ranges`.
|
||
|
||
.. qpdf:option:: --collate[=n]
|
||
|
||
.. help: collate with --pages
|
||
|
||
Collate rather than concatenate pages specified with --pages.
|
||
With a numeric parameter, collate in groups of n. The default
|
||
is 1. Run qpdf --help=page-selection for additional details.
|
||
|
||
This option causes :command:`qpdf` to collate rather than
|
||
concatenate pages specified with :qpdf:ref:`--pages`. With a
|
||
numeric parameter, collate in groups of :samp:`{n}`. The default
|
||
is 1.
|
||
|
||
Please see :ref:`page-selection` for additional details.
|
||
|
||
.. qpdf:option:: --split-pages[=n]
|
||
|
||
.. help: write pages to separate files
|
||
|
||
This option causes qpdf to create separate output files for each
|
||
page or group of pages rather than a single output file.
|
||
|
||
File names are generated from the specified output file as follows:
|
||
|
||
- If the string %d appears in the output file name, it is replaced with a
|
||
zero-padded page range starting from 1
|
||
- Otherwise, if the output file name ends in .pdf (case insensitive), a
|
||
zero-padded page range, preceded by a dash, is inserted before the file
|
||
extension
|
||
- Otherwise, the file name is appended with a zero-padded page range
|
||
preceded by a dash.
|
||
|
||
Page ranges are single page numbers for single-page groups or first-last
|
||
for multi-page groups.
|
||
|
||
Write each group of :samp:`{n}` pages to a separate output file. If
|
||
:samp:`{n}` is not specified, create single pages. Output file
|
||
names are generated as follows:
|
||
|
||
- If the string ``%d`` appears in the output file name, it is
|
||
replaced with a range of zero-padded page numbers starting
|
||
from 1.
|
||
|
||
- Otherwise, if the output file name ends in :file:`.pdf` (case
|
||
insensitive), a zero-padded page range, preceded by a dash, is
|
||
inserted before the file extension.
|
||
|
||
- Otherwise, the file name is appended with a zero-padded page
|
||
range preceded by a dash.
|
||
|
||
Zero padding is added to all page numbers in file names so that all
|
||
the numbers are the same length, which causes the output filenames
|
||
to sort lexically in numerical order.
|
||
|
||
Page ranges are a single number in the case of single-page groups or
|
||
two numbers separated by a dash otherwise.
|
||
|
||
Here are some examples. In these examples, :file:`infile.pdf` has
|
||
12 pages.
|
||
|
||
- ``qpdf --split-pages infile.pdf %d-out``: output files are
|
||
:file:`01-out` through :file:`12-out` with no extension.
|
||
|
||
- ``qpdf --split-pages=2 infile.pdf outfile.pdf``: output files are
|
||
:file:`outfile-01-02.pdf` through :file:`outfile-11-12.pdf`
|
||
|
||
- ``qpdf --split-pages infile.pdf something.else`` would generate
|
||
files :file:`something.else-01` through
|
||
:file:`something.else-12`. The extension ``.else`` is not treated
|
||
in any special way regarding the placement of the number.
|
||
|
||
Note that outlines, threads, and other document-level features of
|
||
the original PDF file are not preserved. For each page of output,
|
||
this option creates an empty PDF and copies a single page from the
|
||
output into it. If you require the document-level data, you will
|
||
have to run :command:`qpdf` with the :qpdf:ref:`--pages` option
|
||
once for each page. Using :qpdf:ref:`--split-pages` is much faster
|
||
if you don't require the document-level data. A future version of
|
||
qpdf may support preservation of some document-level information.
|
||
|
||
.. qpdf:option:: --overlay file [options] --
|
||
|
||
.. help: begin overlay options
|
||
|
||
Overlay pages from another file on the output.
|
||
Run qpdf --help=overlay-underlay for details.
|
||
|
||
Overlay pages from another file on the output.
|
||
|
||
See :ref:`overlay-underlay` for details.
|
||
|
||
.. qpdf:option:: --underlay file [options] --
|
||
|
||
.. help: begin underlay options
|
||
|
||
Underlay pages from another file on the output.
|
||
Run qpdf --help=overlay-underlay for details.
|
||
|
||
Underlay pages from another file on the output.
|
||
|
||
See :ref:`overlay-underlay` for details.
|
||
|
||
.. qpdf:option:: --flatten-rotation
|
||
|
||
.. help: remove rotation from page dictionary
|
||
|
||
For each page that is rotated using the /Rotate key in the
|
||
page's dictionary, remove the /Rotate key and implement the
|
||
identical rotation semantics by modifying the page's contents.
|
||
This can be useful if a broken PDF viewer fails to properly
|
||
consider page rotation metadata.
|
||
|
||
For each page that is rotated using the ``/Rotate`` key in the
|
||
page's dictionary, remove the ``/Rotate`` key and implement the
|
||
identical rotation semantics by modifying the page's contents. This
|
||
option can be useful to prepare files for buggy PDF applications
|
||
that don't properly handle rotated pages. There is usually no
|
||
reason to use this option unless you are working around a specific
|
||
problem.
|
||
|
||
.. qpdf:option:: --flatten-annotations=parameter
|
||
|
||
.. help: push annotations into content
|
||
|
||
Push page annotations into the content streams. This may be
|
||
necessary in some case when printing or splitting files.
|
||
Parameters: "all", "print", "screen".
|
||
|
||
This option collapses annotations into the pages' contents with
|
||
special handling for form fields. Ordinarily, an annotation is
|
||
rendered separately and on top of the page. Combining annotations
|
||
into the page's contents effectively freezes the placement of the
|
||
annotations, making them look right after various page
|
||
transformations. The library functionality backing this option was
|
||
added for the benefit of programs that want to create *n-up* page
|
||
layouts and other similar things that don't work well with
|
||
annotations. The value of :samp:`{parameter}` may be any of the
|
||
following:
|
||
|
||
.. list-table:: Flatten Annotation Parameters
|
||
:widths: 10 80
|
||
:header-rows: 0
|
||
|
||
- - :samp:`all`
|
||
- include all annotations that are not marked invisible or
|
||
hidden
|
||
|
||
- - :samp:`print`
|
||
- only include annotations that should appear when the page is
|
||
printed
|
||
|
||
- - :samp:`screen`
|
||
- omit annotations that should not appear on the screen
|
||
|
||
In a PDF file, interactive form fields have a value and,
|
||
independently, a set of instructions, called an appearance, to
|
||
render the filled-in field. If a form is filled in by a program
|
||
that doesn't know how to update the appearances, they may become
|
||
inconsistent with the fields' values. If qpdf detects this case,
|
||
its default behavior is not to flatten those annotations because
|
||
doing so would cause the value of the form field to be lost. This
|
||
gives you a chance to go back and resave the form with a program
|
||
that knows how to generate appearances. qpdf itself can generate
|
||
appearances with some limitations. See the
|
||
:qpdf:ref:`--generate-appearances` option for details.
|
||
|
||
.. qpdf:option:: --rotate=[+|-]angle[:page-range]
|
||
|
||
.. help: rotate pages
|
||
|
||
Rotate specified pages by multiples of 90 degrees specifying
|
||
either absolute or relative angles. "angle" may be 0, 90, 180,
|
||
or 270. You almost always want to use +angle or -angle rather
|
||
than just angle, as discussed in the manual. Run
|
||
qpdf --help=page-ranges for help with page ranges.
|
||
|
||
Rotate the specified range of pages by the specified angle, which
|
||
must be a multiple of 90 degrees.
|
||
|
||
The value of :samp:`{angle}` may be ``0``, ``90``, ``180``, or ``270``.
|
||
|
||
For a description of the syntax of :samp:`{page-range}`, see
|
||
:ref:`page-ranges`. If the page range is omitted, the rotation is
|
||
applied to all pages.
|
||
|
||
If ``+`` is prepended to :samp:`{angle}`, the angle is added, so an
|
||
angle of ``+90`` indicates a 90-degree clockwise rotation. If ``-``
|
||
is prepended, the angle is subtracted, so ``-90`` is a 90-degree
|
||
counterclockwise rotation and is exactly the same as ``+270``.
|
||
|
||
If neither ``+`` or ``-`` is prepended, the rotation angle is set
|
||
exactly. You almost always want ``+`` or ``-`` since, without
|
||
inspecting the actual PDF code, it is impossible to know whether a
|
||
page that appears to be rotate is rotated "naturally" or has been
|
||
rotated by specifying rotation. For example, if a page appears to
|
||
contain a portrait-mode image rotated by 90 degrees so that the top
|
||
of the image is on the right edge of the page, there is no way to
|
||
tell by visual inspection whether the literal top of the image is
|
||
the top of the page or whether the literal top of the image is the
|
||
right edge and the page is already rotated in the PDF. Specifying a
|
||
rotation angle of ``-90`` will produce an image that appears
|
||
upright in either case. Use of absolute rotation angles should be
|
||
reserved for cases in which you have specific knowledge about the
|
||
way the PDF file is constructed.
|
||
|
||
Examples:
|
||
|
||
- ``qpdf in.pdf out.pdf --rotate=+90:2,4,6 --rotate=+180:7-8``:
|
||
rotate pages 2, 4, and 6 by 90 degrees clockwise from their
|
||
original rotation
|
||
|
||
- ``qpdf in.pdf out.pdf --rotate=+180``: rotate all pages by 180
|
||
degrees
|
||
|
||
- ``qpdf in.pdf out.pdf --rotate=0``: force each page to be displayed
|
||
in its natural orientation, which would undo the effect of any
|
||
rotations previously applied in page metadata.
|
||
|
||
See also :qpdf:ref:`--flatten-rotation`.
|
||
|
||
.. qpdf:option:: --generate-appearances
|
||
|
||
.. help: generate appearances for form fields
|
||
|
||
PDF form fields consist of values and appearances, which may be
|
||
inconsistent with each other if a form field value has been
|
||
modified without updating its appearance. This option tells qpdf
|
||
to generate new appearance streams. There are some limitations,
|
||
which are discussed in the manual.
|
||
|
||
If a file contains interactive form fields and indicates that the
|
||
appearances are out of date with the values of the form, this flag
|
||
will regenerate appearances, subject to a few limitations. Note
|
||
that there is usually no reason to do this, but it can be
|
||
necessary before using the :qpdf:ref:`--flatten-annotations`
|
||
option. Here is a summary of the limitations.
|
||
|
||
- Radio button and checkbox appearances use the pre-set values in
|
||
the PDF file. :command:`qpdf` just makes sure that the correct
|
||
appearance is displayed based on the value of the field. This is
|
||
fine for PDF files that create their forms properly. Some PDF
|
||
writers save appearances for fields when they change, which could
|
||
cause some controls to have inconsistent appearances.
|
||
|
||
- For text fields and list boxes, any characters that fall outside
|
||
of US-ASCII or, if detected, "Windows ANSI" or "Mac Roman"
|
||
encoding, will be replaced by the ``?`` character.
|
||
:command:`qpdf` does not know enough about fonts and encodings to
|
||
correctly represent characters that fall outside of this range.
|
||
|
||
- For variable text fields where the default appearance stream
|
||
specifies that the font should be auto-sized, a fixed font size
|
||
is used rather than calculating the font size.
|
||
|
||
- Quadding is ignored. Quadding is used to specify whether the
|
||
contents of a field should be left, center, or right aligned with
|
||
the field.
|
||
|
||
- Rich text, multi-line, and other more elaborate formatting
|
||
directives are ignored.
|
||
|
||
- There is no support for multi-select fields or signature fields.
|
||
|
||
Appearances generated by :command:`qpdf` should be good enough for
|
||
simple forms consisting of ASCII characters where the original file
|
||
followed the PDF specification and provided template information
|
||
for text field appearances. If :command:`qpdf` doesn't do a good
|
||
enough job with your form, use an external application to save your
|
||
filled-in form before processing it with :command:`qpdf`. Most PDF
|
||
viewers that support filling in of forms will generate appearance
|
||
streams. Some of them will even do it for forms filled in with
|
||
characters outside the original font's character range by embedding
|
||
additional fonts as needed.
|
||
|
||
.. qpdf:option:: --optimize-images
|
||
|
||
.. help: use efficient compression for images
|
||
|
||
Attempt to use DCT (JPEG) compression for images that fall
|
||
within certain constraints as long as doing so decreases the
|
||
size in bytes of the image. See also help for the following
|
||
options:
|
||
--oi-min-width
|
||
--oi-min-height
|
||
--oi-min-area
|
||
--keep-inline-images
|
||
|
||
This flag causes qpdf to recompress all images that are not
|
||
compressed with DCT (JPEG) using DCT compression as long as doing
|
||
so decreases the size in bytes of the image data and the image does
|
||
not fall below minimum specified dimensions. Useful information is
|
||
provided when used in combination with :qpdf:ref:`--verbose`. See
|
||
also the :qpdf:ref:`--oi-min-width`, :qpdf:ref:`--oi-min-height`,
|
||
and :qpdf:ref:`--oi-min-area` options. By default, inline images
|
||
are converted to regular images and optimized as well. Use
|
||
:qpdf:ref:`--keep-inline-images` to prevent inline images from
|
||
being included.
|
||
|
||
.. qpdf:option:: --oi-min-width=width
|
||
|
||
.. help: minimum width for --optimize-images
|
||
|
||
Don't optimize images whose width is below the specified value.
|
||
|
||
Avoid optimizing images whose width is below the specified amount. If
|
||
omitted, the default is 128 pixels. Use 0 for no minimum.
|
||
|
||
.. qpdf:option:: --oi-min-height=height
|
||
|
||
.. help: minimum height for --optimize-images
|
||
|
||
Don't optimize images whose height is below the specified value.
|
||
|
||
Avoid optimizing images whose height is below the specified amount.
|
||
If omitted, the default is 128 pixels. Use 0 for no minimum.
|
||
|
||
.. qpdf:option:: --oi-min-area=area-in-pixels
|
||
|
||
.. help: minimum area for --optimize-images
|
||
|
||
Don't optimize images whose area in pixels is below the specified value.
|
||
|
||
Avoid optimizing images whose pixel count
|
||
(:samp:`{width}` × :samp:`{height}`) is below the specified amount.
|
||
If omitted, the default is 16,384 pixels. Use 0 for no minimum.
|
||
|
||
.. qpdf:option:: --keep-inline-images
|
||
|
||
.. help: exclude inline images from optimization
|
||
|
||
Prevent inline images from being considered by --optimize-images.
|
||
|
||
Prevent inline images from being included in image optimization
|
||
done by :qpdf:ref:`--optimize-images`.
|
||
|
||
.. qpdf:option:: --remove-page-labels
|
||
|
||
.. help: remove explicit page numbers
|
||
|
||
Exclude page labels (explicit page numbers) from the output file.
|
||
|
||
Exclude page labels (explicit page numbers) from the output file.
|
||
|
||
.. _encryption-options:
|
||
|
||
Encryption
|
||
----------
|
||
|
||
.. help-topic encryption: create encrypted files
|
||
|
||
Create encrypted files. Usage:
|
||
|
||
--encrypt user-password owner-password key-length [options] --
|
||
|
||
Either or both of user-password and owner-password may be empty
|
||
strings. key-length may be 40, 128, or 256. Encryption options are
|
||
terminated by "--" by itself.
|
||
|
||
40-bit encryption is insecure, as is 128-bit encryption without
|
||
AES. Use 256-bit encryption unless you have a specific reason to
|
||
use an insecure format, such as testing or compatibility with very
|
||
old viewers. You must use the --allow-weak-crypto to create
|
||
encrypted files that use insecure cryptographic algorithms. The
|
||
--allow-weak-crypto flag appears outside of --encrypt ... --
|
||
(before --encrypt or after --).
|
||
|
||
Available options vary by key length. Not all readers respect all
|
||
restrictions. Different PDF readers respond differently to various
|
||
combinations of options. Sometimes a PDF viewer may show you
|
||
restrictions that differ from what you selected. This is probably
|
||
not a bug in qpdf.
|
||
|
||
Options for 40-bit only:
|
||
--annotate=[y|n] restrict comments, filling forms, and signing
|
||
--extract=[y|n] restrict text/graphic extraction
|
||
--modify=[y|n] restrict document modification
|
||
--print=[y|n] restrict printing
|
||
|
||
Options for 128-bit or 256-bit:
|
||
--accessibility=[y|n] restrict accessibility (usually ignored)
|
||
--annotate=[y|n] restrict commenting/filling form fields
|
||
--assemble=[y|n] restrict document assembly
|
||
--extract=[y|n] restrict text/graphic extraction
|
||
--form=[y|n] restrict filling form fields
|
||
--modify-other=[y|n] restrict other modifications
|
||
--modify=modify-opt control modify access by level
|
||
--print=print-opt control printing access
|
||
--cleartext-metadata prevent encryption of metadata
|
||
|
||
For 128-bit only:
|
||
--use-aes=[y|n] indicates whether to use AES encryption
|
||
--force-V4 forces use of V=4 encryption handler
|
||
|
||
For 256-bit only:
|
||
--force-R5 forces use of deprecated R=5 encryption
|
||
--allow-insecure allow user password with empty owner password
|
||
|
||
Values for print-opt:
|
||
none disallow printing
|
||
low allow only low-resolution printing
|
||
full allow full printing
|
||
|
||
Values for modify-opt:
|
||
none allow no modifications
|
||
assembly allow document assembly only
|
||
form assembly + filling in form fields and signing
|
||
annotate form + commenting and modifying forms
|
||
all allow full document modification
|
||
|
||
This section describes the options used to create encrypted files. For
|
||
other options related to encryption, see also :qpdf:ref:`--decrypt`
|
||
and :qpdf:ref:`--copy-encryption`. For a more in-depth technical
|
||
discussion of how PDF encryption works internally, see
|
||
:ref:`pdf-encryption`.
|
||
|
||
To create an encrypted file, use
|
||
|
||
::
|
||
|
||
--encrypt user-password owner-password key-length [options] --
|
||
|
||
Either or both of :samp:`{user-password}` and :samp:`{owner-password}`
|
||
may be empty strings. :samp:`{key-length}` may be ``40``, ``128``, or
|
||
``256``. Encryption options are terminated by ``--`` by itself.
|
||
|
||
40-bit encryption is insecure, as is 128-bit encryption without AES.
|
||
Use 256-bit encryption unless you have a specific reason to use an
|
||
insecure format, such as testing or compatibility with very old
|
||
viewers. You must use the :qpdf:ref:`--allow-weak-crypto` flag to
|
||
create encrypted files that use insecure cryptographic algorithms. The
|
||
:qpdf:ref:`--allow-weak-crypto` flag appears outside of ``--encrypt
|
||
... --`` (before ``--encrypt`` or after ``--``).
|
||
|
||
If :samp:`{key-length}` is 256, the minimum PDF version is 1.7 with
|
||
extension level 8, and the AES-based encryption format used is the one
|
||
described in the PDF 2.0 specification. Using 128-bit encryption
|
||
forces the PDF version to be at least 1.4, or if AES is used, 1.6.
|
||
Using 40-bit encryption forces the PDF version to be at least 1.3.
|
||
|
||
When 256-bit encryption is used, PDF files with empty owner
|
||
passwords are insecure. To create such files, you must specify the
|
||
:qpdf:ref:`--allow-insecure` option.
|
||
|
||
Available options vary by key length. Not all readers respect all
|
||
restrictions. The default for each permission option is to be fully
|
||
permissive. These restrictions may or may not be enforced by any
|
||
particular reader. :command:`qpdf` allows very granular setting of
|
||
restrictions. Some readers may not recognize the combination of
|
||
options you specify. If you specify certain combinations of
|
||
restrictions and find a reader that doesn't seem to honor them as you
|
||
expect, it is most likely not a bug in :command:`qpdf`. qpdf itself
|
||
does not obey encryption restrictions already imposed on the file.
|
||
Doing so would be meaningless since qpdf can be used to remove
|
||
encryption from the file entirely.
|
||
|
||
Here is a summary of encryption options. Details are provided in the
|
||
help for each option.
|
||
|
||
.. list-table:: Options for 40-bit Encryption Only
|
||
:widths: 30 70
|
||
:header-rows: 0
|
||
|
||
- - ``--annotate=[y|n]``
|
||
- restrict comments, filling forms, and signing
|
||
|
||
- - ``--extract=[y|n]``
|
||
- restrict text/graphic extraction
|
||
|
||
- - ``--modify=[y|n]``
|
||
- restrict document modification
|
||
|
||
- - ``--print=[y|n]``
|
||
- restrict printing
|
||
|
||
.. list-table:: Options for 128-bit or 256-bit Encryption
|
||
:widths: 30 70
|
||
:header-rows: 0
|
||
|
||
- - ``--accessibility=[y|n]``
|
||
- restrict accessibility (usually ignored)
|
||
|
||
- - ``--annotate=[y|n]``
|
||
- restrict commenting/filling form fields
|
||
|
||
- - ``--assemble=[y|n]``
|
||
- restrict document assembly
|
||
|
||
- - ``--extract=[y|n]``
|
||
- restrict text/graphic extraction
|
||
|
||
- - ``--form=[y|n]``
|
||
- restrict filling form fields
|
||
|
||
- - ``--modify-other=[y|n]``
|
||
- restrict other modifications
|
||
|
||
- - ``--modify=modify-opt``
|
||
- control modify access by level
|
||
|
||
- - ``--print=print-opt``
|
||
- control printing access
|
||
|
||
- - ``--cleartext-metadata``
|
||
- prevent encryption of metadata
|
||
|
||
.. list-table:: Options for 128-bit Encryption Only
|
||
:widths: 35 65
|
||
:header-rows: 0
|
||
|
||
- - ``--use-aes=[y|n]``
|
||
- indicates whether to use AES encryption
|
||
|
||
- - ``--force-V4``
|
||
- forces use of V=4 encryption handler
|
||
|
||
.. list-table:: Options for 256-bit Encryption Only
|
||
:widths: 30 70
|
||
:header-rows: 0
|
||
|
||
- - ``--force-R5``
|
||
- forces use of deprecated ``R=5`` encryption algorithm
|
||
|
||
- - ``--allow-insecure``
|
||
- allow user password with empty owner password
|
||
|
||
.. list-table:: Values for :samp:`{print-opt}`
|
||
:widths: 20 80
|
||
:header-rows: 0
|
||
|
||
- - ``none``
|
||
- disallow printing
|
||
|
||
- - ``low``
|
||
- allow only low-resolution printing
|
||
|
||
- - ``full``
|
||
- allow full printing
|
||
|
||
.. list-table:: Values for :samp:`{modify-opt}`
|
||
:widths: 20 80
|
||
:header-rows: 0
|
||
|
||
- - ``none``
|
||
- allow no modifications
|
||
|
||
- - ``assembly``
|
||
- allow document assembly only
|
||
|
||
- - ``form``
|
||
- ``assembly`` permissions plus filling in form fields and
|
||
signing
|
||
|
||
- - ``annotate``
|
||
- ``form`` permissions plus commenting and modifying forms
|
||
|
||
- - ``all``
|
||
- allow full document modification
|
||
|
||
Related Options
|
||
~~~~~~~~~~~~~~~
|
||
|
||
.. qpdf:option:: --accessibility=[y|n]
|
||
|
||
.. help: restrict document accessibility
|
||
|
||
This option is ignored except with very old encryption formats.
|
||
The current PDF specification does not allow restriction of
|
||
document accessibility. This option is not available with 40-bit
|
||
encryption.
|
||
|
||
Enable/disable extraction of text for accessibility to visually
|
||
impaired users. The default is to be fully permissive. The qpdf
|
||
library disregards this field when AES is used with 128-bit
|
||
encryption or when 256-bit encryption is used. You should never
|
||
disable accessibility unless you are explicitly doing so for
|
||
creating test files. The PDF spec says that conforming readers
|
||
should disregard this permission and always allow accessibility.
|
||
|
||
This option is not available with 40-bit encryption.
|
||
|
||
.. qpdf:option:: --annotate=[y|n]
|
||
|
||
.. help: restrict document annotation
|
||
|
||
Enable/disable modifying annotations including making comments
|
||
and filling in form fields. For 128-bit and 256-bit encryption,
|
||
this also enables editing, creating, and deleting form fields
|
||
unless --modify-other=n or --modify=none is also specified.
|
||
|
||
Enable/disable modifying annotations including making comments and
|
||
filling in form fields. The default is to be fully permissive. For
|
||
128-bit and 256-bit encryption, this also enables editing,
|
||
creating, and deleting form fields unless :samp:`--modify-other=n`
|
||
or :samp:`--modify=none` is also specified.
|
||
|
||
.. qpdf:option:: --assemble=[y|n]
|
||
|
||
.. help: restrict document assembly
|
||
|
||
Enable/disable document assembly (rotation and reordering of
|
||
pages). This option is not available with 40-bit encryption.
|
||
|
||
Enable/disable document assembly (rotation and reordering of
|
||
pages). The default is to be fully permissive.
|
||
|
||
This option is not available with 40-bit encryption.
|
||
|
||
.. qpdf:option:: --extract=[y|n]
|
||
|
||
.. help: restrict text/graphic extraction
|
||
|
||
Enable/disable text/graphic extraction for purposes other than
|
||
accessibility.
|
||
|
||
Enable/disable text/graphic extraction for purposes other than
|
||
accessibility. The default is to be fully permissive.
|
||
|
||
.. qpdf:option:: --form=[y|n]
|
||
|
||
.. help: restrict form filling
|
||
|
||
Enable/disable whether filling form fields is allowed even if
|
||
modification of annotations is disabled. This option is not
|
||
available with 40-bit encryption.
|
||
|
||
Enable/disable whether filling form fields is allowed even if
|
||
modification of annotations is disabled. The default is to be fully
|
||
permissive.
|
||
|
||
This option is not available with 40-bit encryption.
|
||
|
||
.. qpdf:option:: --modify-other=[y|n]
|
||
|
||
.. help: restrict other modifications
|
||
|
||
Enable/disable modifications not controlled by --assemble,
|
||
--annotate, or --form. --modify-other=n is implied by any of the
|
||
other --modify options. This option is not available with 40-bit
|
||
encryption.
|
||
|
||
Enable/disable modifications not controlled by
|
||
:qpdf:ref:`--assemble`, :qpdf:ref:`--annotate`, or
|
||
:qpdf:ref:`--form`. ``--modify-other=n`` is implied by any of the
|
||
other :qpdf:ref:`--modify` options except for ``--modify=all``. The
|
||
default is to be fully permissive.
|
||
|
||
This option is not available with 40-bit encryption.
|
||
|
||
.. qpdf:option:: --modify=modify-opt
|
||
|
||
.. help: restrict document modification
|
||
|
||
For 40-bit files, modify-opt may only be y or n and controls all
|
||
aspects of document modification.
|
||
|
||
For 128-bit and 256-bit encryption, modify-opt values allow
|
||
enabling and disabling levels of restriction in a manner similar
|
||
to how some PDF creation tools do it. modify-opt values map to
|
||
other combinations of options as follows:
|
||
|
||
all: allow full modification (the default)
|
||
annotate: --modify-other=n
|
||
form: --modify-other=n --annotate=n
|
||
assembly: --modify-other=n --annotate=n --form=n
|
||
none: --modify-other=n --annotate=n --form=n --assemble=n
|
||
|
||
For 40-bit files, :samp:`{modify-opt}` may only be ``y`` or ``n``
|
||
and controls all aspects of document modification. The default is
|
||
to be fully permissive.
|
||
|
||
For 128-bit and 256-bit encryption, :samp:`{modify-opt}` values
|
||
allow enabling and disabling levels of restriction in a manner
|
||
similar to how some PDF creation tools do it:
|
||
|
||
.. list-table:: :samp:`{modify-opt}` for 128-bit and 256-bit Encryption
|
||
:widths: 10 80
|
||
:header-rows: 0
|
||
|
||
- - ``none``
|
||
- allow no modifications
|
||
|
||
- - ``assembly``
|
||
- allow document assembly only
|
||
|
||
- - ``form``
|
||
- ``assembly`` permissions plus filling in form fields and
|
||
signing
|
||
|
||
- - ``annotate``
|
||
- ``form`` permissions plus commenting and modifying forms
|
||
|
||
- - ``all``
|
||
- allow full document modification (the default)
|
||
|
||
Modify options correspond to the more granular options as follows:
|
||
|
||
.. list-table:: Mapping :samp:`{modify-opt}` to Other Options
|
||
:widths: 10 80
|
||
:header-rows: 0
|
||
|
||
- - ``none``
|
||
- ``--modify-other=n --annotate=n --form=n --assemble=n``
|
||
|
||
- - ``assembly``
|
||
- ``--modify-other=n --annotate=n --form=n``
|
||
|
||
- - ``form``
|
||
- ``--modify-other=n --annotate=n``
|
||
|
||
- - ``annotate``
|
||
- ``--modify-other=n``
|
||
|
||
- - ``all``
|
||
- no other modify options (the default)
|
||
|
||
You can combine this option with the options listed above. If you
|
||
do, later options override earlier options.
|
||
|
||
.. qpdf:option:: --print=print-opt
|
||
|
||
.. help: restrict printing
|
||
|
||
Control what kind of printing is allowed. For 40-bit encryption,
|
||
print-opt may only be y or n and enables or disables all
|
||
printing. For 128-bit and 256-bit encryption, print-opt may have
|
||
the following values:
|
||
|
||
none: disallow printing
|
||
low: allow low-resolution printing only
|
||
full: allow full printing (the default)
|
||
|
||
Control what kind of printing is allowed. The default is to be
|
||
fully permissive. For 40-bit encryption, :samp:`{print-opt}` may
|
||
only be ``y`` or ``n`` and enables or disables all printing. For
|
||
128-bit and 256-bit encryption, :samp:`{print-opt}` may have the
|
||
following values:
|
||
|
||
.. list-table:: :samp:`{print-opt}` Values
|
||
:widths: 10 80
|
||
:header-rows: 0
|
||
|
||
- - :samp:`none`
|
||
- disallow printing
|
||
|
||
- - :samp:`low`
|
||
- allow low-resolution printing only
|
||
|
||
- - :samp:`full`
|
||
- allow full printing (the default)
|
||
|
||
.. qpdf:option:: --cleartext-metadata
|
||
|
||
.. help: don't encrypt metadata
|
||
|
||
If specified, don't encrypt document metadata even when
|
||
encrypting the rest of the document. This option is not
|
||
available with 40-bit encryption.
|
||
|
||
If specified, any metadata stream in the document will be left
|
||
unencrypted even if the rest of the document is encrypted. This also
|
||
forces the PDF version to be at least 1.5.
|
||
|
||
This option is not available with 40-bit encryption.
|
||
|
||
.. qpdf:option:: --use-aes=[y|n]
|
||
|
||
.. help: use AES with 128-bit encryption
|
||
|
||
Enables/disables use of the more secure AES encryption with
|
||
128-bit encryption. Specifying --use-aes=y forces the PDF
|
||
version to be at least 1.6. This option is only available with
|
||
128-bit encryption. The default is "n" for compatibility
|
||
reasons. Use 256-bit encryption instead.
|
||
|
||
Enables/disables use of the more secure AES encryption with 128-bit
|
||
encryption. Specifying ``--use-aes=y`` forces the PDF version to be
|
||
at least 1.6. This option is only available with 128-bit
|
||
encryption. The default is ``n`` for compatibility reasons. Use
|
||
256-bit encryption instead.
|
||
|
||
.. qpdf:option:: --allow-insecure
|
||
|
||
.. help: allow empty owner passwords
|
||
|
||
Allow creation of PDF files with empty owner passwords and
|
||
non-empty user passwords when using 256-bit encryption.
|
||
|
||
Allow creation of PDF files with 256-bit keys where the user
|
||
password is non-empty and the owner password is empty. Files
|
||
created in this way are insecure since they can be opened without a
|
||
password, and restrictions will not be enforced. Users would
|
||
ordinarily never want to create such files. If you are using qpdf
|
||
to intentionally created strange files for testing (a valid use of
|
||
qpdf!), this option allows you to create such insecure files. This
|
||
option is only available with 256-bit encryption.
|
||
|
||
See :ref:`pdf-passwords` for a more technical discussion of this
|
||
issue.
|
||
|
||
.. qpdf:option:: --force-V4
|
||
|
||
.. help: force V=4 in encryption dictionary
|
||
|
||
This option is for testing and is never needed in practice since
|
||
qpdf does this automatically when needed.
|
||
|
||
Use of this option forces the ``V`` and ``R`` parameters in the
|
||
document's encryption dictionary to be set to the value ``4``. As
|
||
qpdf will automatically do this when required, there is no reason
|
||
to ever use this option. It exists primarily for use in testing
|
||
qpdf itself. This option also forces the PDF version to be at least
|
||
1.5.
|
||
|
||
.. qpdf:option:: --force-R5
|
||
|
||
.. help: use unsupported R=5 encryption
|
||
|
||
Use an undocumented, unsupported, deprecated encryption
|
||
algorithm that existed only in Acrobat version IX. This option
|
||
should not be used except for compatibility testing.
|
||
|
||
Use an undocumented, unsupported, deprecated encryption algorithm
|
||
that existed only in Acrobat version IX. This option should not be
|
||
used except for compatibility testing. If specified, qpdf sets the
|
||
minimum version to 1.7 at extension level 3.
|
||
|
||
.. _page-selection:
|
||
|
||
Page Selection
|
||
--------------
|
||
|
||
.. help-topic page-selection: select pages from one or more files
|
||
|
||
Use the --pages option to select pages from multiple files. Usage:
|
||
|
||
qpdf in.pdf --pages input-file [--password=password] [page-range] \
|
||
[...] -- out.pdf
|
||
|
||
Between --pages and the -- that terminates pages option, repeat
|
||
the following:
|
||
|
||
filename [--password=password] [page-range]
|
||
|
||
Document-level information, such as outlines, tags, etc., is taken
|
||
from in.pdf and is preserved in out.pdf. You can use --empty in place
|
||
of an input file to start from an empty file and just copy pages
|
||
equally from all files. You can use "." as a shorthand for the
|
||
primary input file (if not --empty). In the above example, "."
|
||
would refer to in.pdf.
|
||
|
||
Use --password=password to specify the password for a
|
||
password-protected input file. If the same input file is used more
|
||
than once, you only need to supply the password the first time. If
|
||
the page range is omitted, all pages are selected.
|
||
|
||
Run qpdf --help=page-ranges for help with page ranges.
|
||
|
||
Use --collate=n to cause pages to be collated in groups of n pages
|
||
(default 1) instead of concatenating the input.
|
||
|
||
Examples:
|
||
|
||
- Start with in.pdf and append all pages from a.pdf and the even
|
||
pages from b.pdf, and write the output to out.pdf. Document-level
|
||
information from in.pdf is retained. Note the use of "." to refer
|
||
to in.pdf.
|
||
|
||
qpdf in.pdf --pages . a.pdf b.pdf:even -- out.pdf
|
||
|
||
- Take all the pages from a.pdf, all the pages from b.pdf in
|
||
reverse, and only pages 3 and 6 from c.pdf and write the result
|
||
to out.pdf. Use password "x" to open b.pdf:
|
||
|
||
qpdf --empty --pages a.pdf b.pdf --password=x z-1 c.pdf 3,6
|
||
|
||
More examples are in the manual.
|
||
|
||
:command:`qpdf` allows you to use the :qpdf:ref:`--pages` option to
|
||
split and merge PDF files by selecting pages from one or more input
|
||
files.
|
||
|
||
Usage: :samp:`qpdf {in.pdf} --pages input-file [--password={password}] [{page-range}] [...] -- {out.pdf}`
|
||
|
||
Between ``--pages`` and the ``--`` that terminates pages option,
|
||
repeat the following:
|
||
|
||
:samp:`{filename} [--password={password}] [{page-range}]`
|
||
|
||
Notes:
|
||
- The password option is needed only for password-protected files.
|
||
If you specify the same file more than once, you only need to supply
|
||
the password the first time.
|
||
|
||
- The page range may be omitted. If omitted, all pages are included.
|
||
|
||
- Document-level information, such as outlines, tags, etc., is taken
|
||
from the primary input file (in the above example, :file:`in.pdf`)
|
||
and is preserved in :file:`out.pdf`. You can use
|
||
:qpdf:ref:`--empty` in place of an input file to start from an
|
||
empty file and just copy pages equally from all files.
|
||
|
||
- You can use ``.`` as a shorthand for the primary input file, if not
|
||
empty.
|
||
|
||
See :ref:`page-ranges` for help on specifying a page range.
|
||
|
||
Use :samp:`--collate={n}` to cause pages to be collated in groups of
|
||
:samp:`{n}` pages (default 1) instead of concatenating the input. Note
|
||
that the :qpdf:ref:`--collate` appears outside of ``--pages ... --``
|
||
(before ``--pages`` or after ``--``). Pages are pulled from each
|
||
document in turn. When a document is out of pages, it is skipped. See
|
||
examples below.
|
||
|
||
Examples
|
||
~~~~~~~~
|
||
|
||
- Start with :file:`in.pdf` and append all pages from :file:`a.pdf`
|
||
and the even pages from :file:`b.pdf`, and write the output to
|
||
:file:`out.pdf`. Document-level information from :file:`in.pdf` is
|
||
retained. Note the use of ``.`` to refer to :file:`in.pdf`.
|
||
|
||
::
|
||
|
||
qpdf in.pdf --pages . a.pdf b.pdf:even -- out.pdf
|
||
|
||
|
||
- Take all the pages from :file:`a.pdf`, all the pages from
|
||
:file:`b.pdf` in reverse, and only pages 3 and 6 from :file:`c.pdf`
|
||
and write the result to :file:`out.pdf`. Document-level metadata is
|
||
discarded from all input files. The password ``x`` is used to open
|
||
:file:`b.pdf`.
|
||
|
||
::
|
||
|
||
qpdf --empty --pages a.pdf b.pdf --password=x z-1 c.pdf 3,6
|
||
|
||
- Scan a document with double-sided printing by scanning the fronts
|
||
into :file:`odd.pdf` and the backs into :file:`even.pdf`. Collate
|
||
the results into :file:`all.pdf`. This takes the first page of
|
||
:file:`odd.pdf`, the first page of :file:`even.pdf`, the second page
|
||
of :file:`odd.pdf`, the second page of :file:`even.pdf`, etc.
|
||
|
||
::
|
||
|
||
qpdf --collate odd.pdf --pages . even.pdf -- all.pdf
|
||
OR
|
||
qpdf --collate --empty --pages odd.pdf even.pdf -- all.pdf
|
||
|
||
- When collating, any number of files and page ranges can be
|
||
specified. If any file has fewer pages, that file is just skipped
|
||
when its pages have all been included. For example, if you ran
|
||
|
||
::
|
||
|
||
qpdf --collate --empty --pages a.pdf 1-5 b.pdf 6-4 c.pdf r1 -- out.pdf
|
||
|
||
you would get the following pages in this order:
|
||
|
||
- a.pdf page 1
|
||
|
||
- b.pdf page 6
|
||
|
||
- c.pdf last page
|
||
|
||
- a.pdf page 2
|
||
|
||
- b.pdf page 5
|
||
|
||
- a.pdf page 3
|
||
|
||
- b.pdf page 4
|
||
|
||
- a.pdf page 4
|
||
|
||
- a.pdf page 5
|
||
|
||
- You can specify a numeric parameter to :qpdf:ref:`--collate`. With
|
||
:samp:`--collate={n}`, pull groups of :samp:`{n}` pages from each
|
||
file, as always, stopping when there are no more pages. For example,
|
||
if you ran
|
||
|
||
::
|
||
|
||
qpdf --collate=2 --empty --pages a.pdf 1-5 b.pdf 6-4 c.pdf r1 -- out.pdf
|
||
|
||
you would get the following pages in this order:
|
||
|
||
- a.pdf page 1
|
||
|
||
- a.pdf page 2
|
||
|
||
- b.pdf page 6
|
||
|
||
- b.pdf page 5
|
||
|
||
- c.pdf last page
|
||
|
||
- a.pdf page 3
|
||
|
||
- a.pdf page 4
|
||
|
||
- b.pdf page 4
|
||
|
||
- a.pdf page 5
|
||
|
||
- Take pages 1 through 5 from :file:`file1.pdf` and pages 11 through
|
||
15 in reverse from :file:`file2.pdf`, taking document-level metadata
|
||
from :file:`file2.pdf`.
|
||
|
||
::
|
||
|
||
qpdf file2.pdf --pages file1.pdf 1-5 . 15-11 -- outfile.pdf
|
||
|
||
- Here's a more contrived example. If, for some reason, you wanted to
|
||
take the first page of an encrypted file called
|
||
:file:`encrypted.pdf` with password ``pass`` and repeat it twice in
|
||
an output file without any shared data between the two copies of
|
||
page 1, and if you wanted to drop document-level metadata but
|
||
preserve encryption, you could run
|
||
|
||
::
|
||
|
||
qpdf --empty --copy-encryption=encrypted.pdf \
|
||
--encryption-file-password=pass \
|
||
--pages encrypted.pdf --password=pass 1 \
|
||
./encrypted.pdf --password=pass 1 -- \
|
||
outfile.pdf
|
||
|
||
Note that we had to specify the password all three times because
|
||
giving a password as :qpdf:ref:`--encryption-file-password` doesn't
|
||
count for page selection, and as far as qpdf is concerned,
|
||
:file:`encrypted.pdf` and :file:`./encrypted.pdf` are separate
|
||
files. (This is by design. See :ref:`page-limitations` for a
|
||
discussion.) These are all corner cases that most users should
|
||
hopefully never have to be bothered with.
|
||
|
||
.. _page-limitations:
|
||
|
||
Limitations
|
||
~~~~~~~~~~~
|
||
|
||
With the exception of page labels (page numbers), :command:`qpdf`
|
||
doesn't yet have full support for handling document-level data as it
|
||
relates to pages. Certain document-level features such as form fields,
|
||
outlines (bookmarks), and article tags among others, are copied in
|
||
their entirety from the primary input file. Starting with qpdf version
|
||
8.3, page labels are preserved from all files unless
|
||
:qpdf:ref:`--remove-page-labels` is specified.
|
||
|
||
.. If updating this after limitations are removed or reduced,
|
||
recheck --split-pages as well.
|
||
|
||
It is expected that a future version of :command:`qpdf` will have more
|
||
complete and configurable behavior regarding document-level metadata.
|
||
In the meantime, semantics of splitting and merging vary across
|
||
features. For example, the document's outlines (bookmarks) point to
|
||
actual page objects, so if you select some pages and not others,
|
||
bookmarks that point to pages that are in the output file will work,
|
||
and remaining bookmarks will not work. If you don't want to preserve
|
||
the primary file's metadata, use :qpdf:ref:`--empty` as the primary
|
||
input file.
|
||
|
||
Visit `qpdf issues labeled with "pages"
|
||
<https://github.com/qpdf/qpdf/issues?q=is%3Aopen+is%3Aissue+label%3Apages>`__
|
||
or look at the :file:`TODO` file in the qpdf source distribution for
|
||
some of the ideas.
|
||
|
||
.. NOTE:
|
||
|
||
The workaround described in the following paragraph is mentioned in
|
||
the documentation in more than one place. Searching for ./ should
|
||
help find them. It is also in the test suite. I believe there are
|
||
several valid uses cases for doing this, and so it is my intention
|
||
to leave the behavior of treating different paths to the same file
|
||
as separate even if the above limitations are removed. See also
|
||
https://github.com/qpdf/qpdf/issues/399
|
||
|
||
Prior to :command:`qpdf` version 8.4, it was not possible to specify
|
||
the same page from the same file directly more than once, and a
|
||
workaround of specifying the same file in more than one way was
|
||
required. Version 8.4 removes this limitation, but when the same page
|
||
is copied more than once, all its data is shared between the pages.
|
||
Sometimes this is fine, but sometimes it may not work correctly,
|
||
particularly if there are form fields or you intend to perform other
|
||
modifications on one of the pages. A future version of qpdf should
|
||
address this more completely. You can work around this by specifying
|
||
the same file in two different ways. For example :command:`qpdf
|
||
in.pdf --pages . 1 ./in.pdf 1 -- out.pdf` would create a file with two
|
||
copies of the first page of the input, and the two copies would not
|
||
share any objects in common. This includes fonts, images, and anything
|
||
else the page references.
|
||
|
||
.. _overlay-underlay:
|
||
|
||
Overlay and Underlay
|
||
--------------------
|
||
|
||
.. help-topic overlay-underlay: overlay/underlay pages from other files
|
||
|
||
These options allow pages from another file to be overlaid or
|
||
underlaid on the primary output. Overlaid pages are drawn on top of
|
||
the destination page and may obscure the page. Underlaid pages are
|
||
drawn below the destination page. Usage:
|
||
|
||
{--overlay|--underlay} file
|
||
[--password=password]
|
||
[--to=page-range]
|
||
[--from=[page-range]]
|
||
[--repeat=page-range]
|
||
--
|
||
|
||
Note the use of "--" by itself to terminate overlay/underlay options.
|
||
|
||
For overlay and underlay, a file and optional password are specified, along
|
||
with a series of optional page ranges. The default behavior is that each
|
||
page of the overlay or underlay file is imposed on the corresponding page
|
||
of the primary output until it runs out of pages, and any extra pages are
|
||
ignored. You can also give a page range with --repeat to cause
|
||
those pages to be repeated after the original pages are exhausted.
|
||
|
||
Run qpdf --help=page-ranges for help with page ranges.
|
||
|
||
You can use :command:`qpdf` to overlay or underlay pages from other
|
||
files onto the output generated by qpdf. Specify overlay or underlay
|
||
as follows:
|
||
|
||
::
|
||
|
||
{--overlay|--underlay} file [options] --
|
||
|
||
Overlay and underlay options are processed late, so they can be
|
||
combined with other options like merging and will apply to the final
|
||
output. The ``--overlay`` and ``--underlay`` options work the same
|
||
way, except underlay pages are drawn underneath the page to which they
|
||
are applied, possibly obscured by the original page, and overlay files
|
||
are drawn on top of the page to which they are applied, possibly
|
||
obscuring the page. You can combine overlay and underlay, but you can
|
||
only specify each option at most one time.
|
||
|
||
The default behavior of overlay and underlay is that pages are taken
|
||
from the overlay/underlay file in sequence and applied to
|
||
corresponding pages in the output until there are no more output
|
||
pages. If the overlay or underlay file runs out of pages, remaining
|
||
output pages are left alone. This behavior can be modified by options,
|
||
which are provided between the ``--overlay`` or ``--underlay`` flag
|
||
and the ``--`` option. The following options are supported:
|
||
|
||
.. qpdf:option:: --to=page-range
|
||
|
||
.. help: destination pages for underlay/overlay
|
||
|
||
Specify the range of pages in the primary output to apply
|
||
overlay/underlay to. See qpdf --help=page-ranges for help with
|
||
the page range syntax.
|
||
|
||
Specify a page range (see :ref:`page-ranges`) that indicates which
|
||
pages in the output should have the overlay/underlay applied. If not
|
||
specified, overlay/underlay are applied to all pages.
|
||
|
||
.. qpdf:option:: --from=[page-range]
|
||
|
||
.. help: source pages for underlay/overlay
|
||
|
||
Specify pages from the overlay/underlay file that are applied to
|
||
the destination pages. See qpdf --help=page-ranges for help
|
||
with the page range syntax. The page range may be omitted
|
||
if --repeat is used.
|
||
|
||
Specify a page range that indicates which pages in the
|
||
overlay/underlay file will be used for overlay or underlay. If not
|
||
specified, all pages will be used. The "from" pages are used until
|
||
they are exhausted, after which any pages specified with
|
||
:qpdf:ref:`--repeat` are used. If you are using the
|
||
:qpdf:ref:`--repeat` option, you can use ``--from=`` to provide an
|
||
empty set of "from" pages.
|
||
|
||
This Can be left empty by omitting
|
||
:samp:`{page-range}`
|
||
|
||
.. qpdf:option:: --repeat=page-range
|
||
|
||
.. help: overlay/underlay pages to repeat
|
||
|
||
Specify pages from the overlay/underlay that are repeated after
|
||
"from" pages have been exhausted. See qpdf --help=page-ranges
|
||
for help with the page range syntax.
|
||
|
||
Specify an optional page range that indicates which pages in the
|
||
overlay/underlay file will be repeated after the "from" pages are used
|
||
up. If you want to apply a repeat a range of pages starting with the
|
||
first page of output, you can explicitly use ``--from=``.
|
||
|
||
Examples
|
||
~~~~~~~~
|
||
|
||
- Overlay the first three pages from file :file:`o.pdf` onto the first
|
||
three pages of the output, then overlay page 4 from :file:`o.pdf`
|
||
onto pages 4 and 5 of the output. Leave remaining output pages
|
||
untouched.
|
||
|
||
::
|
||
|
||
qpdf in.pdf --overlay o.pdf --to=1-5 --from=1-3 --repeat=4 -- out.pdf
|
||
|
||
|
||
- Underlay page 1 of :file:`footer.pdf` on all odd output pages, and
|
||
underlay page 2 of :file:`footer.pdf` on all even output pages.
|
||
|
||
::
|
||
|
||
qpdf in.pdf --underlay footer.pdf --from= --repeat=1,2 -- out.pdf
|
||
|
||
- Combine two files and overlay the single page from watermark.pdf on
|
||
the result.
|
||
|
||
::
|
||
|
||
qpdf --empty --pages a.pdf b.pdf -- \
|
||
--overlay watermark.pdf --from= --repeat=1 -- out.pdf
|
||
|
||
.. _attachments:
|
||
|
||
Embedded Files/Attachments
|
||
--------------------------
|
||
|
||
.. help-topic attachments: work with embedded files
|
||
|
||
It is possible to list, add, or delete embedded files (also known
|
||
as attachments) and to copy attachments from other files. See help
|
||
on individual options for details. Run qpdf --help=add-attachment
|
||
for additional details about adding attachments. See also
|
||
--help=--list-attachments and --help=--show-attachment.
|
||
|
||
It is possible to list, add, or delete embedded files (also known as
|
||
attachments) and to copy attachments from other files. See also
|
||
:qpdf:ref:`--list-attachments` and :qpdf:ref:`--show-attachment`.
|
||
|
||
Related Options
|
||
~~~~~~~~~~~~~~~
|
||
|
||
.. qpdf:option:: --add-attachment file [options] --
|
||
|
||
.. help: start add attachment options
|
||
|
||
The --add-attachment flag and its options may be repeated to add
|
||
multiple attachments. Run qpdf --help=add-attachment for details.
|
||
|
||
This flag starts add attachment options, which are used to add
|
||
attachments to a file.
|
||
|
||
The ``--add-attachment`` flag and its options may be repeated to
|
||
add multiple attachments. Please see :ref:`add-attachment` for
|
||
additional details.
|
||
|
||
.. qpdf:option:: --copy-attachments-from file [options] --
|
||
|
||
.. help: start copy attachment options
|
||
|
||
The --copy-attachments-from flag and its options may be repeated
|
||
to copy attachments from multiple files. Run
|
||
qpdf --help=copy-attachments for details.
|
||
|
||
This flag starts copy attachment options, which are used to copy
|
||
attachments from other files.
|
||
|
||
The ``--copy-attachments-from`` flag and its options may be
|
||
repeated to copy attachments from multiple files. Please see
|
||
:ref:`copy-attachments` for additional details.
|
||
|
||
.. qpdf:option:: --remove-attachment=key
|
||
|
||
.. help: remove an embedded file
|
||
|
||
Remove an embedded file using its key. Get the key with
|
||
--list-attachments.
|
||
|
||
Remove the specified attachment. This doesn't only remove the
|
||
attachment from the embedded files table but also clears out the
|
||
file specification to ensure that the attachment is actually not
|
||
present in the output file. That means that any potential internal
|
||
links to the attachment will be broken. Run with :qpdf:ref:`--verbose` to
|
||
see status of the removal. Use :qpdf:ref:`--list-attachments` to find
|
||
the attachment key. This option may be repeated to remove multiple
|
||
attachments.
|
||
|
||
.. _pdf-dates:
|
||
|
||
PDF Date Format
|
||
~~~~~~~~~~~~~~~
|
||
|
||
.. help-topic pdf-dates: PDF date format
|
||
|
||
When a date is required, the date should conform to the PDF date
|
||
format specification, which is "D:yyyymmddhhmmssz" where "z" is
|
||
either literally upper case "Z" for UTC or a timezone offset in
|
||
the form "-hh'mm'" or "+hh'mm'". Negative timezone offsets indicate
|
||
time before UTC. Positive offsets indicate how far after. For
|
||
example, US Eastern Standard Time (America/New_York) is "-05'00'",
|
||
and Indian Standard Time (Asia/Calcutta) is "+05'30'".
|
||
|
||
Examples:
|
||
- D:20210207161528-05'00' February 7, 2021 at 4:15:28 p.m.
|
||
- D:20210207211528Z February 7, 2021 at 21:15:28 UTC
|
||
|
||
When a date is required, the date should conform to the PDF date
|
||
format specification, which is :samp:`D:{yyyymmddhhmmssz}` where
|
||
:samp:`{z}` is either literally upper case ``Z`` for UTC or a
|
||
timezone offset in the form :samp:`{-hh'mm'}` or :samp:`{+hh'mm'}`.
|
||
Negative timezone offsets indicate time before UTC. Positive offsets
|
||
indicate how far after. For example, US Eastern Standard Time
|
||
(America/New_York) is ``-05'00'``, and Indian Standard Time
|
||
(Asia/Calcutta) is ``+05'30'``.
|
||
|
||
.. list-table:: PDF Date Examples
|
||
:widths: 30 70
|
||
:header-rows: 0
|
||
|
||
- - ``D:20210207161528-05'00'``
|
||
- February 7, 2021 at 4:15:28 p.m.
|
||
|
||
- - ``D:20210207211528Z``
|
||
- February 7, 2021 at 21:15:28 UTC
|
||
|
||
.. _add-attachment:
|
||
|
||
Options for Adding Attachments
|
||
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
||
|
||
.. help-topic add-attachment: attach (embed) files
|
||
|
||
The options listed below appear between --add-attachment and its
|
||
terminating "--".
|
||
|
||
These options are valid between :qpdf:ref:`--add-attachment` and ``--``.
|
||
|
||
.. qpdf:option:: --key=key
|
||
|
||
.. help: specify attachment key
|
||
|
||
Specify the key to use for the attachment in the embedded files
|
||
table. It defaults to the last element (basename) of the
|
||
attached file's filename.
|
||
|
||
Specify the key to use for the attachment in the embedded files
|
||
table. It defaults to the last element of the attached file's
|
||
filename. For example, if you say ``--add-attachment
|
||
/home/user/image.png``, the default key will be just ``image.png``.
|
||
|
||
.. qpdf:option:: --filename=name
|
||
|
||
.. help: set attachment's displayed filename
|
||
|
||
Specify the filename to be used for the attachment. This is what
|
||
is usually displayed to the user and is the name most graphical
|
||
PDF viewers will use when saving a file. It defaults to the last
|
||
element (basename) of the attached file's filename.
|
||
|
||
Specify the filename to be used for the attachment. This is what is
|
||
usually displayed to the user and is the name most graphical PDF
|
||
viewers will use when saving a file. It defaults to the last
|
||
element of the attached file's filename. For example, if you say
|
||
``--add-attachment /home/user/image.png``, the default key will be
|
||
just ``image.png``.
|
||
|
||
.. qpdf:option:: --creationdate=date
|
||
|
||
.. help: set attachment's creation date
|
||
|
||
Specify the attachment's creation date in PDF format; defaults
|
||
to the current time. Run qpdf --help=pdf-dates for information
|
||
about the date format.
|
||
|
||
Specify the attachment's creation date in PDF format; defaults to
|
||
the current time. See :ref:`pdf-dates` for information about the
|
||
date format.
|
||
|
||
.. qpdf:option:: --moddate=date
|
||
|
||
.. help: set attachment's modification date
|
||
|
||
Specify the attachment's modification date in PDF format;
|
||
defaults to the current time. Run qpdf --help=pdf-dates for
|
||
information about the date format.
|
||
|
||
Specify the attachment's modification date in PDF format; defaults
|
||
to the current time. See :ref:`pdf-dates` for information about the
|
||
date format.
|
||
|
||
.. qpdf:option:: --mimetype=type/subtype
|
||
|
||
.. help: attachment mime type, e.g. application/pdf
|
||
|
||
Specify the mime type for the attachment, such as text/plain,
|
||
application/pdf, image/png, etc.
|
||
|
||
Specify the mime type for the attachment, such as ``text/plain``,
|
||
``application/pdf``, ``image/png``, etc. The qpdf library does not
|
||
automatically determine the mime type. In a UNIX-like environment,
|
||
the :command:`file` command can often provide this information. In
|
||
MacOS, you can use :samp:`file -I {filename}`. In Linux, it's
|
||
:samp:`file -i {filename}`.
|
||
|
||
Implementation note: the mime type appears in a field called
|
||
``/Subtype`` in the PDF file, but that field actually includes the
|
||
full type and subtype of the mime type. This is because ``/Type``
|
||
already means something else in PDF.
|
||
|
||
.. qpdf:option:: --description="text"
|
||
|
||
.. help: set attachment's description
|
||
|
||
Supply descriptive text for the attachment, displayed by some
|
||
PDF viewers.
|
||
|
||
Supply descriptive text for the attachment, displayed by some PDF
|
||
viewers.
|
||
|
||
.. qpdf:option:: --replace
|
||
|
||
.. help: replace attachment with same key
|
||
|
||
Indicate that any existing attachment with the same key should
|
||
be replaced by the new attachment. Otherwise, qpdf gives an
|
||
error if an attachment with that key is already present.
|
||
|
||
Indicate that any existing attachment with the same key should be
|
||
replaced by the new attachment. Otherwise, :command:`qpdf` gives an
|
||
error if an attachment with that key is already present.
|
||
|
||
.. _copy-attachments:
|
||
|
||
Options for Copying Attachments
|
||
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
||
|
||
.. help-topic copy-attachments: copy attachments from another file
|
||
|
||
The options listed below appear between --copy-attachments-from and
|
||
its terminating "--".
|
||
|
||
To copy attachments from a password-protected file, use
|
||
the --password option after the file name.
|
||
|
||
Options in this section are valid between
|
||
:qpdf:ref:`--copy-attachments-from` and ``--``.
|
||
|
||
.. qpdf:option:: --prefix=prefix
|
||
|
||
.. help: key prefix for copying attachments
|
||
|
||
Prepend a prefix to each key; may be needed if there are
|
||
duplicate attachment keys. This affects the key only, not the
|
||
file name.
|
||
|
||
Only required if the file from which attachments are being copied
|
||
has attachments with keys that conflict with attachments already
|
||
in the file. In this case, the specified prefix will be prepended
|
||
to each key. This affects only the key in the embedded files
|
||
table, not the file name. The PDF specification doesn't preclude
|
||
multiple attachments having the same file name.
|
||
|
||
.. _inspection-options:
|
||
|
||
PDF Inspection
|
||
--------------
|
||
|
||
.. help-topic inspection: inspect PDF files
|
||
|
||
These options provide tools for inspecting PDF files. When any of
|
||
the options in this section are specified, no output file may be
|
||
given.
|
||
|
||
These options provide tools for inspecting PDF files. When any of the
|
||
options in this section are specified, no output file may be given.
|
||
|
||
Related Options
|
||
~~~~~~~~~~~~~~~
|
||
|
||
.. qpdf:option:: --is-encrypted
|
||
|
||
.. help: silently test whether a file is encrypted
|
||
|
||
Silently exit with a code indicating the file's encryption status:
|
||
|
||
0: the file is encrypted
|
||
1: not used
|
||
2: the file is not encrypted
|
||
|
||
This can be used with password-protected files even if you don't
|
||
know the password.
|
||
|
||
Silently exit with a code indicating the file's encryption status:
|
||
|
||
.. list-table:: Exit Codes for ``--is-encrypted``
|
||
:widths: 5 80
|
||
:header-rows: 0
|
||
|
||
- - ``0``
|
||
- the file is encrypted
|
||
|
||
- - ``1``
|
||
- not used
|
||
|
||
- - ``2``
|
||
- the file is not encrypted
|
||
|
||
This option can be used for password-protected files even if you
|
||
don't know the password.
|
||
|
||
This option is useful for shell scripts. Other options are ignored
|
||
if this is given. This option is mutually exclusive with
|
||
:qpdf:ref:`--requires-password`. Both this option and
|
||
:qpdf:ref:`--requires-password` exit with status ``2`` for
|
||
non-encrypted files.
|
||
|
||
.. qpdf:option:: --requires-password
|
||
|
||
.. help: silently test a file's password
|
||
|
||
Silently exit with a code indicating the file's password status:
|
||
|
||
0: a password, other than as supplied, is required
|
||
1: not used
|
||
2: the file is not encrypted
|
||
3: the file is encrypted, and correct password (if any) has been supplied
|
||
|
||
Silently exit with a code indicating the file's password status:
|
||
|
||
.. list-table:: Exit Codes for ``--requires-password``
|
||
:widths: 5 80
|
||
:header-rows: 0
|
||
|
||
- - ``0``
|
||
- a password, other than as supplied, is required
|
||
|
||
- - ``1``
|
||
- not used
|
||
|
||
- - ``2``
|
||
- the file is not encrypted
|
||
|
||
- - ``3``
|
||
- the file is encrypted, and correct password (if any) has
|
||
been supplied
|
||
|
||
Use with the :qpdf:ref:`--password` option to specify the password
|
||
to test.
|
||
|
||
The choice of exit status ``0`` to mean that a password is required
|
||
is to enable code like
|
||
|
||
.. code-block:: bash
|
||
|
||
if [ qpdf --requires-password file.pdf ]; then
|
||
# prompt for password
|
||
fi
|
||
|
||
If a password is supplied with :qpdf:ref:`--password`, that
|
||
password is used to open the file just as with any normal
|
||
invocation of :command:`qpdf`. That means that using this option
|
||
with :qpdf:ref:`--password` can be used to check the correctness of
|
||
the password. In that case, an exit status of ``3`` means the file
|
||
works with the supplied password. This option is mutually exclusive
|
||
with :qpdf:ref:`--is-encrypted`. Both this option and
|
||
:qpdf:ref:`--is-encrypted` exit with status ``2`` for non-encrypted
|
||
files.
|
||
|
||
.. qpdf:option:: --check
|
||
|
||
.. help: partially check whether PDF is valid
|
||
|
||
Check the structure of the PDF file as well as a number of other
|
||
aspects of the file, and write information about the file to
|
||
standard output. Note that qpdf does not perform any validation
|
||
of the actual PDF page content or semantic correctness of the
|
||
PDF file. It merely checks that the PDF file is syntactically
|
||
valid. See also qpdf --help=exit-status.
|
||
|
||
Check the file's structure as well as encryption, linearization,
|
||
and encoding of stream data, and write information about the file
|
||
to standard output. An exit status of ``0`` indicates syntactic
|
||
correctness of the PDF file. Note that :samp:`--check` writes
|
||
nothing to standard error when everything is valid, so if you are
|
||
using this to programmatically validate files in bulk, it is safe
|
||
to run without output redirected to :file:`/dev/null` and just
|
||
check for a ``0`` exit code.
|
||
|
||
A file for which :samp:`--check` reports no errors may still have
|
||
errors in stream data content or may contain constructs that don't
|
||
conform to the PDF specification, but it should be syntactically
|
||
valid. If :samp:`--check` reports any errors, qpdf will exit with a
|
||
status of ``2``. There are some recoverable conditions that
|
||
:samp:`--check` detects. These are issued as warnings instead of
|
||
errors. If qpdf finds no errors but finds warnings, it will exit
|
||
with a status of ``3``. When :samp:`--check` is combined with other
|
||
options, checks are always performed before any other options are
|
||
processed. For erroneous files, :samp:`--check` will cause qpdf to
|
||
attempt to recover, after which other options are effectively
|
||
operating on the recovered file. Combining :samp:`--check` with
|
||
other options in this way can be useful for manually recovering
|
||
severely damaged files.
|
||
|
||
See also :ref:`exit-status`.
|
||
|
||
.. qpdf:option:: --show-encryption
|
||
|
||
.. help: information about encrypted files
|
||
|
||
Show document encryption parameters. Also show the document's
|
||
user password if the owner password is given and the file was
|
||
encrypted using older encryption formats that allow user
|
||
password recovery.
|
||
|
||
This option shows document encryption parameters. It also shows the
|
||
document's user password if the owner password is given and the
|
||
file was encrypted using older encryption formats that allow user
|
||
password recovery. (See :ref:`pdf-encryption` for a technical
|
||
discussion of this feature.) The output of ``--show-encryption`` is
|
||
included in the output of :qpdf:ref:`--check`.
|
||
|
||
.. qpdf:option:: --show-encryption-key
|
||
|
||
.. help: show key with --show-encryption
|
||
|
||
When used with --show-encryption or --check, causes the
|
||
underlying encryption key to be displayed.
|
||
|
||
When encryption information is being displayed, as when
|
||
:qpdf:ref:`--check` or :qpdf:ref:`--show-encryption` is given, display the
|
||
computed or retrieved encryption key as a hexadecimal string. This
|
||
value is not ordinarily useful to users, but it can be used as the
|
||
parameter to :qpdf:ref:`--password` if the :qpdf:ref:`--password-is-hex-key`
|
||
is specified. Note that, when PDF files are encrypted, passwords
|
||
and other metadata are used only to compute an encryption key, and
|
||
the encryption key is what is actually used for encryption. This
|
||
enables retrieval of that key. See :ref:`pdf-encryption` for a
|
||
technical discussion.
|
||
|
||
.. qpdf:option:: --check-linearization
|
||
|
||
.. help: check linearization tables
|
||
|
||
Check to see whether a file is linearized and, if so, whether
|
||
the linearization hint tables are correct.
|
||
|
||
Check to see whether a file is linearized and, if so, whether the
|
||
linearization hint tables are correct. qpdf does not check all
|
||
aspects of linearization. A linearized PDF file with linearization
|
||
errors that is otherwise correct is almost always readable by a PDF
|
||
viewer. As such, "errors" in PDF linearization are treated by
|
||
:command:`qpdf` as warnings.
|
||
|
||
.. qpdf:option:: --show-linearization
|
||
|
||
.. help: show linearization hint tables
|
||
|
||
Check and display all data in the linearization hint tables.
|
||
|
||
Check and display all data in the linearization hint tables.
|
||
|
||
.. qpdf:option:: --show-xref
|
||
|
||
.. help: show cross reference data
|
||
|
||
Show the contents of the cross-reference table or stream (object
|
||
locations in the file) in a human-readable form. This is
|
||
especially useful for files with cross-reference streams, which
|
||
are stored in a binary format.
|
||
|
||
Show the contents of the cross-reference table or stream in a
|
||
human-readable form. The cross-reference data gives the offset of
|
||
regular objects and the object stream ID and 0-based index within
|
||
the object stream for compressed objects. This is especially useful
|
||
for files with cross-reference streams, which are stored in a
|
||
binary format. If the file is invalid and cross reference table
|
||
reconstruction is performed, this option will show the information
|
||
in the reconstructed table.
|
||
|
||
.. qpdf:option:: --show-object={trailer|obj[,gen]}
|
||
|
||
.. help: show contents of an object
|
||
|
||
Show the contents of the given object. This is especially useful
|
||
for inspecting objects that are inside of object streams (also
|
||
known as "compressed objects").
|
||
|
||
Show the contents of the given object. This is especially useful
|
||
for inspecting objects that are inside of object streams (also
|
||
known as "compressed objects").
|
||
|
||
.. qpdf:option:: --raw-stream-data
|
||
|
||
.. help: show raw stream data
|
||
|
||
When used with --show-object, if the object is a stream, write
|
||
the raw (compressed) binary stream data to standard output
|
||
instead of the object's contents. See also
|
||
--filtered-stream-data.
|
||
|
||
When used with :qpdf:ref:`--show-object`, if the object is a
|
||
stream, write the raw (compressed) binary stream data to standard
|
||
output instead of the object's contents. Avoid combining this with
|
||
other inspection options to avoid commingling the stream data with
|
||
other output. See also :qpdf:ref:`--filtered-stream-data`.
|
||
|
||
.. qpdf:option:: --filtered-stream-data
|
||
|
||
.. help: show filtered stream data
|
||
|
||
When used with --show-object, if the object is a stream, write
|
||
the filtered (uncompressed, potentially binary) stream data to
|
||
standard output instead of the object's contents. See also
|
||
--raw-stream-data.
|
||
|
||
When used with :qpdf:ref:`--show-object`, if the object is a stream,
|
||
write the filtered (uncompressed, potentially binary) stream data
|
||
to standard output instead of the object's contents. If the stream
|
||
is filtered using filters that qpdf does not support, an error will
|
||
be issued. This option acts as if ``--decode-level=all`` was
|
||
specified (see :qpdf:ref:`--decode-level`), so it will uncompress
|
||
images compressed with supported lossy compression schemes. Avoid
|
||
combining this with other inspection options to avoid commingling
|
||
the stream data with other output.
|
||
|
||
This option may be combined with :qpdf:ref:`--normalize-content`.
|
||
If you do this, qpdf will attempt to run content normalization even
|
||
if the stream is not a content stream, which will probably produce
|
||
unusable results.
|
||
|
||
See also :qpdf:ref:`--raw-stream-data`.
|
||
|
||
.. qpdf:option:: --show-npages
|
||
|
||
.. help: show number of pages
|
||
|
||
Print the number of pages in the input file on a line by itself.
|
||
Useful for scripts.
|
||
|
||
Print the number of pages in the input file on a line by itself.
|
||
Since the number of pages appears by itself on a line, this option
|
||
can be useful for scripting if you need to know the number of pages
|
||
in a file.
|
||
|
||
.. qpdf:option:: --show-pages
|
||
|
||
.. help: display page dictionary information
|
||
|
||
Show the object and generation number for each page dictionary
|
||
object and for each content stream associated with the page.
|
||
|
||
Show the object and generation number for each page dictionary
|
||
object and for each content stream associated with the page. Having
|
||
this information makes it more convenient to inspect objects from a
|
||
particular page. See also :qpdf:ref:`--with-images`.
|
||
|
||
.. qpdf:option:: --with-images
|
||
|
||
.. help: include image details with --show-pages
|
||
|
||
When used with --show-pages, also shows the object and
|
||
generation numbers for the image objects on each page.
|
||
|
||
When used with :qpdf:ref:`--show-pages`, also shows the object and
|
||
generation numbers for the image objects on each page.
|
||
|
||
.. qpdf:option:: --list-attachments
|
||
|
||
.. help: list embedded files
|
||
|
||
Show the key and stream number for each embedded file. Combine
|
||
with --verbose for more detailed information.
|
||
|
||
Show the *key* and stream number for each embedded file. With
|
||
:qpdf:ref:`--verbose`, additional information, including preferred
|
||
file name, description, dates, and more are also displayed. The key
|
||
is usually but not always equal to the file name and is needed by
|
||
some of the other options. See also :ref:`attachments`. Note that
|
||
this option displays dates in PDF timestamp syntax. When attachment
|
||
information is included in json output in the ``"attachments"`` key
|
||
(see :qpdf:ref:`--json`), dates are shown (just within that object)
|
||
in ISO-8601 format.
|
||
|
||
.. qpdf:option:: --show-attachment=key
|
||
|
||
.. help: export an embedded file
|
||
|
||
Write the contents of the specified attachment to standard
|
||
output as binary data. Get the key with --list-attachments.
|
||
|
||
Write the contents of the specified attachment to standard output
|
||
as binary data. The key should match one of the keys shown by
|
||
:qpdf:ref:`--list-attachments`. If this option is given more than
|
||
once, only the last attachment will be shown. See also
|
||
:ref:`attachments`.
|
||
|
||
.. _json-options:
|
||
|
||
JSON Options
|
||
------------
|
||
|
||
.. help-topic json: JSON output for PDF information
|
||
|
||
Show information about the PDF file in JSON format. Please see the
|
||
JSON chapter in the qpdf manual for details.
|
||
|
||
It is possible to view information about PDF files in a JSON format.
|
||
See :ref:`json` for details about the qpdf JSON format.
|
||
|
||
Related Options
|
||
~~~~~~~~~~~~~~~
|
||
|
||
.. qpdf:option:: --json[=version]
|
||
|
||
.. help: show file in JSON format
|
||
|
||
Generate a JSON representation of the file. This is described in
|
||
depth in the JSON section of the manual. "version" may be a
|
||
specific version or "latest" (the default). Run qpdf --json-help
|
||
for a description of the generated JSON object.
|
||
|
||
Generate a JSON representation of the file. This is described in
|
||
depth in :ref:`json`. The version parameter can be used to specify
|
||
which version of the qpdf JSON format should be output. The version
|
||
number be a number or ``latest``. The default is ``latest``. As of
|
||
qpdf 11, the latest version is ``2``. If you have code that reads
|
||
qpdf JSON output, you can tell what version of the JSON output you
|
||
have from the ``"version"`` key in the output. Use the
|
||
:qpdf:ref:`--json-help` option to get a description of the JSON
|
||
object.
|
||
|
||
Starting with qpdf 11, when this option is specified, an output
|
||
file is optional (for backward compatibility) and defaults to
|
||
standard output. You may specify an output file to write the JSON
|
||
to a file rather than standard output. (Example: ``qpdf --json
|
||
in.pdf out.json``)
|
||
|
||
Stream data is only included if :qpdf:ref:`--json-output` is
|
||
specified or if a value other than ``none`` is passed to
|
||
:qpdf:ref:`--json-stream-data`.
|
||
|
||
.. qpdf:option:: --json-help[=version]
|
||
|
||
.. help: show format of JSON output
|
||
|
||
Describe the format of the JSON output by writing to standard
|
||
output a JSON object with the same keys and with values
|
||
containing descriptive text.
|
||
|
||
Describe the format of the corresponding version of JSON output by
|
||
writing to standard output a JSON object with the same structure as
|
||
the JSON generated by qpdf. In the output written by
|
||
``--json-help``, each key's value is a description of the key. The
|
||
specific contract guaranteed by qpdf in its JSON representation is
|
||
explained in more detail in the :ref:`json`. The default version of
|
||
help is version ``2``, as with the :qpdf:ref:`--json` flag.
|
||
|
||
.. qpdf:option:: --json-key=key
|
||
|
||
.. help: limit which keys are in JSON output
|
||
|
||
This option is repeatable. If given, only the specified
|
||
top-level keys will be included in the JSON output. Otherwise,
|
||
all keys will be included. With --json-output, when not given,
|
||
only the "qpdf" key will appear in the output.
|
||
|
||
This option is repeatable. If given, only the specified top-level
|
||
keys will be included in the JSON output. Otherwise, all keys will
|
||
be included. If not given, all keys will be included, unless
|
||
:qpdf:ref:`--json-output` was specified, in which case, only the
|
||
``"qpdf"`` key will be included by default. If
|
||
:qpdf:ref:`--json-output` was not given, the ``version`` and
|
||
``parameters`` keys will always appear in the output.
|
||
|
||
.. qpdf:option:: --json-object={trailer|obj[,gen]}
|
||
|
||
.. help: limit which objects are in JSON
|
||
|
||
This option is repeatable. If given, only specified objects will
|
||
be shown in the "objects" key of the JSON output. Otherwise, all
|
||
objects will be shown.
|
||
|
||
This option is repeatable. If given, only specified objects will be
|
||
shown in the objects dictionary in the JSON output. Otherwise, all
|
||
objects will be shown. See :ref:`json` for details about the qpdf
|
||
JSON format.
|
||
|
||
.. qpdf:option:: --json-stream-data={none|inline|file}
|
||
|
||
.. help: how to handle streams in json output
|
||
|
||
When used with --json, this option controls whether streams in
|
||
json output should be omitted, written inline (base64-encoded)
|
||
or written to a file. If "file" is chosen, the file will be the
|
||
name of the output file appended with -nnn where nnn is the
|
||
object number. The prefix can be overridden with
|
||
--json-stream-prefix. The default is "none", except
|
||
when --json-output is specified, in which case the default is
|
||
"inline".
|
||
|
||
When used with :qpdf:ref:`--json`, this option controls
|
||
whether streams in JSON output should be omitted, written inline
|
||
(base64-encoded) or written to a file. If ``file`` is chosen, the
|
||
file will be the name of the output file appended with
|
||
:samp:`-{nnn}` where :samp:`{nnn}` is the object number. The stream
|
||
data file prefix can be overridden with
|
||
:qpdf:ref:`--json-stream-prefix`. The default value is ``none``,
|
||
except when :qpdf:ref:`--json-output` is specified, in which case
|
||
the default is ``inline``.
|
||
|
||
.. qpdf:option:: --json-stream-prefix=file-prefix
|
||
|
||
.. help: prefix for json stream data files
|
||
|
||
When used with --json-stream-data=file, --json-stream-data=file-prefix
|
||
sets the prefix for stream data files, overriding the default,
|
||
which is to use the output file name. Whatever is given here
|
||
will be appended with -nnn to create the name of the file that
|
||
will contain the data for the stream stream in object nnn.
|
||
|
||
When used with ``--json-stream-data=file``,
|
||
``--json-stream-data=file-prefix`` sets the prefix for stream data
|
||
files, overriding the default, which is to use the output file
|
||
name. Whatever is given here will be appended with :samp:`-{nnn}`
|
||
to create the name of the file that will contain the data for the
|
||
stream stream in object :samp:`{nnn}`.
|
||
|
||
.. qpdf:option:: --json-output[=version]
|
||
|
||
.. help: apply defaults for JSON serialization
|
||
|
||
Implies --json=version. Changes default values for certain
|
||
options so that the JSON output written is the most faithful
|
||
representation of the original PDF and contains no additional
|
||
JSON keys. See also --json-stream-data, --json-stream-prefix,
|
||
and --decode-level.
|
||
|
||
Implies :qpdf:ref:`--json` at the specified version. This option
|
||
changes several default values, all of which can be overridden by
|
||
specifying the stated option:
|
||
|
||
- The default value for :qpdf:ref:`--json-stream-data` changes from
|
||
``none`` to ``inline``.
|
||
|
||
- The default value for :qpdf:ref:`--decode-level` changes from
|
||
``generalized`` to ``none``.
|
||
|
||
- By default, only the ``"qpdf"`` key is included in the JSON
|
||
output, but you can add additional keys with
|
||
:qpdf:ref:`--json-key`.
|
||
|
||
- The ``"version"`` and ``"parameters"`` keys will be excluded from
|
||
the JSON output.
|
||
|
||
If you want to look at the contents of streams easily as you would
|
||
in QDF mode (see :ref:`qdf`), you can use
|
||
``--decode-level=generalized`` and ``--json-stream-data=file`` for
|
||
a convenient way to do that.
|
||
|
||
.. qpdf:option:: --json-input
|
||
|
||
.. help: input file is qpdf JSON
|
||
|
||
Treat the input file as a JSON file in qpdf JSON format. See the
|
||
"qpdf JSON Format" section of the manual for information about
|
||
how to use this option.
|
||
|
||
Treat the input file as a JSON file in qpdf JSON format. The input
|
||
file must be complete and include all stream data. The JSON version
|
||
must be at least 2. All top-level keys are ignored except for
|
||
``"qpdf"``. For information about converting between PDF and JSON,
|
||
please see :ref:`json`.
|
||
|
||
.. qpdf:option:: --update-from-json=qpdf-json-file
|
||
|
||
.. help: update a PDF from qpdf JSON
|
||
|
||
Update a PDF file from a JSON file. Please see the "qpdf JSON"
|
||
chapter of the manual for information about how to use this
|
||
option.
|
||
|
||
This option updates a PDF file from the specified qpdf JSON file.
|
||
For a information about how to use this option, please see
|
||
:ref:`json`.
|
||
|
||
.. _test-options:
|
||
|
||
Options for Testing or Debugging
|
||
--------------------------------
|
||
|
||
.. help-topic testing: options for testing or debugging
|
||
|
||
The options below are useful when writing automated test code that
|
||
includes files created by qpdf or when testing qpdf itself.
|
||
|
||
The options below are useful when writing automated test code that
|
||
includes files created by qpdf or when testing qpdf itself. When
|
||
changes are made to qpdf, care is taken to avoid gratuitously changing
|
||
the output of PDF files. This is to make it easier to do direct
|
||
comparisons in test suites with files created by qpdf. However, there
|
||
are no guarantees that the PDF output won't change such as in the
|
||
event of a bug fix or feature enhancement to some aspect of the output
|
||
that qpdf creates.
|
||
|
||
.. _idempotency:
|
||
|
||
Idempotency
|
||
~~~~~~~~~~~
|
||
|
||
Note about idempotency of byte-for-byte content: there is no
|
||
expectation that qpdf is idempotent in the general case. In other
|
||
words, there is no expectation that, when qpdf is run on its own
|
||
output, it will create *byte-for-byte* identical output, even though
|
||
it will create semantically identical files. There are a variety of
|
||
reasons for this including document ID generation, which includes a
|
||
random element, as well as the interaction of stream length encoding
|
||
with dictionary key sorting.
|
||
|
||
It is possible to get idempotent behavior by using the
|
||
:qpdf:ref:`--static-id` or :qpdf:ref:`--deterministic-id` option with
|
||
qpdf and running it *three* times so that you are processing the
|
||
output of qpdf on its own previous output. For example, in this
|
||
sequence of commands:
|
||
|
||
::
|
||
|
||
qpdf any-file.pdf 1.pdf
|
||
qpdf --static-id 1.pdf 2.pdf
|
||
qpdf --static-id 2.pdf 3.pdf
|
||
|
||
the files :file:`2.pdf` and :file:`3.pdf` should be *byte-for-byte*
|
||
identical. The qpdf test suite relies on this behavior. See also
|
||
:qpdf:ref:`--static-aes-iv`.
|
||
|
||
Related Options
|
||
~~~~~~~~~~~~~~~
|
||
|
||
.. qpdf:option:: --static-id
|
||
|
||
.. help: use a fixed document ID
|
||
|
||
Use a fixed value for the document ID. This is intended for
|
||
testing only. Never use it for production files. See also
|
||
qpdf --help=--deterministic-id.
|
||
|
||
Use a fixed value for the document ID (``/ID`` in the trailer).
|
||
**This is intended for testing only. Never use it for production
|
||
files.** If you are trying to get the same ID each time for a given
|
||
file and you are not generating encrypted files, consider using the
|
||
:qpdf:ref:`--deterministic-id` option.
|
||
|
||
.. qpdf:option:: --static-aes-iv
|
||
|
||
.. help: use a fixed AES vector
|
||
|
||
Use a static initialization vector for AES-CBC. This is intended
|
||
for testing only so that output files can be reproducible. Never
|
||
use it for production files. This option is not secure since it
|
||
significantly weakens the encryption.
|
||
|
||
Use a static initialization vector for AES-CBC. This is intended
|
||
for testing only so that output files can be reproducible. Never
|
||
use it for production files. **This option in particular is not
|
||
secure since it significantly weakens the encryption.** When
|
||
combined with :qpdf:ref:`--static-id` and using the three-step
|
||
process described in :ref:`idempotency`, it is possible to create
|
||
byte-for-byte idempotent output with PDF files that use 256-bit
|
||
encryption to assist with creating reproducible test suites.
|
||
|
||
.. qpdf:option:: --linearize-pass1=file
|
||
|
||
.. help: save pass 1 of linearization
|
||
|
||
Write the first pass of linearization to the named file. The
|
||
resulting file is not a valid PDF file. This option is useful only
|
||
for debugging qpdf.
|
||
|
||
Write the first pass of linearization to the named file. *The
|
||
resulting file is not a valid PDF file.* This option is useful only
|
||
for debugging ``QPDFWriter``'s linearization code. When qpdf
|
||
linearizes files, it writes the file in two passes, using the first
|
||
pass to calculate sizes and offsets that are required for hint
|
||
tables and the linearization dictionary. Ordinarily, the first pass
|
||
is discarded. This option enables it to be captured, allowing
|
||
inspection of the file before values calculated in pass 1 are
|
||
inserted into the file for pass 2.
|
||
|
||
.. qpdf:option:: --test-json-schema
|
||
|
||
.. help: test generated json against schema
|
||
|
||
This is used by qpdf's test suite to check consistency between
|
||
the output of qpdf --json and the output of qpdf --json-help.
|
||
|
||
This is used by qpdf's test suite to check consistency between the
|
||
output of ``qpdf --json`` and the output of ``qpdf --json-help``.
|
||
This option causes an extra copy of the generated JSON to appear in
|
||
memory and is therefore unsuitable for use with large files. This
|
||
is why it's also not on by default.
|
||
|
||
.. qpdf:option:: --report-memory-usage
|
||
|
||
.. help: best effort report of memory usage
|
||
|
||
This is used by qpdf's performance test suite to report the
|
||
maximum amount of memory used in supported environments.
|
||
|
||
This is used by qpdf's performance test suite to report the maximum
|
||
amount of memory used in supported environments.
|
||
|
||
.. _unicode-passwords:
|
||
|
||
Unicode Passwords
|
||
-----------------
|
||
|
||
At the library API level, all methods that perform encryption and
|
||
decryption interpret passwords as strings of bytes. It is up to the
|
||
caller to ensure that they are appropriately encoded. Starting with qpdf
|
||
version 8.4.0, qpdf will attempt to make this easier for you when
|
||
interacting with qpdf via its command line interface. The PDF specification
|
||
requires passwords used to encrypt files with 40-bit or 128-bit
|
||
encryption to be encoded with PDF Doc encoding. This encoding is a
|
||
single-byte encoding that supports ISO-Latin-1 and a handful of other
|
||
commonly used characters. It has a large overlap with Windows ANSI but
|
||
is not exactly the same. There is generally no way to provide PDF Doc
|
||
encoded strings on the command line. As such, qpdf versions prior to
|
||
8.4.0 would often create PDF files that couldn't be opened with other
|
||
software when given a password with non-ASCII characters to encrypt a
|
||
file with 40-bit or 128-bit encryption. Starting with qpdf 8.4.0, qpdf
|
||
recognizes the encoding of the parameter and transcodes it as needed.
|
||
The rest of this section provides the details about exactly how qpdf
|
||
behaves. Most users will not need to know this information, but it might
|
||
be useful if you have been working around qpdf's old behavior or if you
|
||
are using qpdf to generate encrypted files for testing other PDF
|
||
software.
|
||
|
||
A note about Windows: when qpdf builds, it attempts to determine what it
|
||
has to do to use ``wmain`` instead of ``main`` on Windows. The ``wmain``
|
||
function is an alternative entry point that receives all arguments as
|
||
UTF-16-encoded strings. When qpdf starts up this way, it converts all
|
||
the strings to UTF-8 encoding and then invokes the regular main. This
|
||
means that, as far as qpdf is concerned, it receives its command-line
|
||
arguments with UTF-8 encoding, just as it would in any modern Linux or
|
||
UNIX environment.
|
||
|
||
If a file is being encrypted with 40-bit or 128-bit encryption and the
|
||
supplied password is not a valid UTF-8 string, qpdf will fall back to
|
||
the behavior of interpreting the password as a string of bytes. If you
|
||
have old scripts that encrypt files by passing the output of
|
||
:command:`iconv` to qpdf, you no longer need to do that,
|
||
but if you do, qpdf should still work. The only exception would be for
|
||
the extremely unlikely case of a password that is encoded with a
|
||
single-byte encoding but also happens to be valid UTF-8. Such a password
|
||
would contain strings of even numbers of characters that alternate
|
||
between accented letters and symbols. In the extremely unlikely event
|
||
that you are intentionally using such passwords and qpdf is thwarting
|
||
you by interpreting them as UTF-8, you can use
|
||
:samp:`--password-mode=bytes` to suppress qpdf's
|
||
automatic behavior.
|
||
|
||
The :qpdf:ref:`--password-mode` option, as described earlier
|
||
in this chapter, can be used to change qpdf's interpretation of supplied
|
||
passwords. There are very few reasons to use this option. One would be
|
||
the unlikely case described in the previous paragraph in which the
|
||
supplied password happens to be valid UTF-8 but isn't supposed to be
|
||
UTF-8. Your best bet would be just to provide the password as a valid
|
||
UTF-8 string, but you could also use
|
||
:samp:`--password-mode=bytes`. Another reason to use
|
||
:samp:`--password-mode=bytes` would be to intentionally
|
||
generate PDF files encrypted with passwords that are not properly
|
||
encoded. The qpdf test suite does this to generate invalid files for the
|
||
purpose of testing its password recovery capability. If you were trying
|
||
to create intentionally incorrect files for a similar purposes, the
|
||
:samp:`bytes` password mode can enable you to do this.
|
||
|
||
When qpdf attempts to decrypt a file with a password that contains
|
||
non-ASCII characters, it will generate a list of alternative passwords
|
||
by attempting to interpret the password as each of a handful of
|
||
different coding systems and then transcode them to the required format.
|
||
This helps to compensate for the supplied password being given in the
|
||
wrong coding system, such as would happen if you used the
|
||
:command:`iconv` workaround that was previously needed.
|
||
It also generates passwords by doing the reverse operation: translating
|
||
from correct in incorrect encoding of the password. This would enable
|
||
qpdf to decrypt files using passwords that were improperly encoded by
|
||
whatever software encrypted the files, including older versions of qpdf
|
||
invoked without properly encoded passwords. The combination of these two
|
||
recovery methods should make qpdf transparently open most encrypted
|
||
files with the password supplied correctly but in the wrong coding
|
||
system. There are no real downsides to this behavior, but if you don't
|
||
want qpdf to do this, you can use the
|
||
:qpdf:ref:`--suppress-password-recovery` option. One reason
|
||
to do that is to ensure that you know the exact password that was used
|
||
to encrypt the file.
|
||
|
||
With these changes, qpdf now generates compliant passwords in most
|
||
cases. There are still some exceptions. In particular, the PDF
|
||
specification directs compliant writers to normalize Unicode passwords
|
||
and to perform certain transformations on passwords with bidirectional
|
||
text. Implementing this functionality requires using a real Unicode
|
||
library like ICU. If a client application that uses qpdf wants to do
|
||
this, the qpdf library will accept the resulting passwords, but qpdf
|
||
will not perform these transformations itself. It is possible that this
|
||
will be addressed in a future version of qpdf. The ``QPDFWriter``
|
||
methods that enable encryption on the output file accept passwords as
|
||
strings of bytes.
|
||
|
||
Please note that the :qpdf:ref:`--password-is-hex-key` option is
|
||
unrelated to all this. That flag bypasses the normal process of going
|
||
from password to encryption key entirely, allowing the raw
|
||
encryption key to be specified directly. That behavior is useful for
|
||
forensic purposes or for brute-force recovery of files with unknown
|
||
passwords and has nothing to do with the document's actual passwords.
|