<p>Released to the public domain wherever applicable. Elsewhere, consider it released under the <ahref="http://www.wtfpl.net/txt/copying/">WTFPLv2</a>.</p>
<p>Even bashbot is written in bash, it depends on commands typically available in a Unix/Linux Environment. More concrete on the common commands provided by recent versions of <ahref="https://en.wikipedia.org/wiki/List_of_GNU_Core_Utilities_commands">coreutils</a>, <ahref="https://en.wikipedia.org/wiki/BusyBox#Commands">busybox</a> or <ahref="https://landley.net/toybox/help.html">toybox</a>, see <ahref="doc/7_develop.md#common-commands">Developer Notes</a></p>
<p><strong>Note for MacOS and BSD Users:</strong> As bashbot heavily uses modern bash and (gnu) grep/sed features, bashbot will not run without installing additional software, see <ahref="doc/0_install.md">Install Bashbot</a></p>
<p><strong>Note for embedded systems:</strong> busybox or toybox ONLY is not sufficient, you need a to install a "real" bash, see also <ahref="doc/0_install.md">Install Bashbot</a></p>
<p>Bashbot <ahref="https://github.com/topkecleon/telegram-bot-bash">Documentation</a> and <ahref="https://github.com/topkecleon/telegram-bot-bash/releases">Downloads</a> are available on www.github.com</p>
<p>To install and run bashbot you need access to a linux/unix command line. If you don't know how to get access to a linux/unix command line you should stop reading here :-(</p>
<p>In addition you need a <ahref="https://telegram.org">Telegram client</a> and a mobile phone to <ahref="https://telegramguide.com/create-a-telegram-account/">register an account</a>. If you don't want to register for Telegram you should stop reading here ;-)</p>
<p>After you're registered to Telegram send a message to <ahref="https://telegram.me/botfather">@botfather</a>, <ahref="doc/1_firstbot.md">create a new Telegram Bot token</a> and write it down. You need the token to install the bot.</p>
<p>Create a new directory, change to it: <code>mkdir tbb; cd tbb</code> and download the latest '*.tar.gz' file from <ahref="https://github.com/topkecleon/telegram-bot-bash/releases">https://github.com/topkecleon/telegram-bot-bash/releases</a>. This can be done with the commands:</p>
<p>Extract the '*.tar.gz' file and change to bashbot directory: <code>tar -xzf *.tar.gz; cd telegram-bot-bash</code>, install bashbot: <code>./bashbot.sh init</code> and enter your bot token when asked. All other questions can be answered by hitting the <Return> key.</p>
<p>Since version 0.96 bashbot log commands received/send and connection errors. If you start bashbot in debug mode bash stdout, stderr and all send/received telegram message are logged also.</p>
<p>Bash scripts in general are not designed to be bullet proof, so consider this Bot as a proof of concept. Bash programmers often struggle with 'quoting hell' and globbing, see <ahref="https://unix.stackexchange.com/questions/171346/security-implications-of-forgetting-to-quote-a-variable-in-bash-posix-shells">Implications of wrong quoting</a></p>
<p>Whenever you are processing input from untrusted sources (messages, files, network) you must be as careful as possible, e.g. set IFS appropriate, disable globbing (set -f) and quote everything. In addition delete unused scripts and examples from your Bot, e.g. scripts 'notify', 'calc', 'question', and disable all not used commands.</p>
<p><strong>Note:</strong> Up to version v0.941 (mai/22/2020) telegram-bot-bash had a remote code execution (RCE) bug, please update if you use an older version! see <ahref="https://github.com/topkecleon/telegram-bot-bash/issues/125">Issue #125</a></p>
<p>One of the most powerful features of unix shells is variable and command substitution using <code>${}</code> and <code>$()</code>, but as they are expanded in double quotes, this can lead to RCE and information disclosing bugs in complex scripts like bashbot. So it's more secure to escape or remove '$' in input from user, files or network.</p>
<p>A powerful tool to improve your scripts is <code>shellcheck</code>. You can <ahref="https://www.shellcheck.net/">use it online</a> or <ahref="https://github.com/koalaman/shellcheck#installing">install shellcheck locally</a>. Shellcheck is used extensively in bashbot development to ensure a high code quality, e.g. it's not allowed to push changes without passing all shellcheck tests. In addition bashbot has a <ahref="doc/7_develop.md">test suite</a> to check if important functionality is working as expected.</p>
<p>If you're writing a script and it is taking external input (from the user as arguments or file system...), you shouldn't use echo to display it. <ahref="https://unix.stackexchange.com/a/6581">Use printf whenever possible</a></p>
<divclass="sourceCode"id="cb5"><preclass="sourceCode bash"><codeclass="sourceCode bash"><spanid="cb5-1"><ahref="#cb5-1"aria-hidden="true"tabindex="-1"></a><spanclass="co"># very simple</span></span>
<spanid="cb5-2"><ahref="#cb5-2"aria-hidden="true"tabindex="-1"></a><spanclass="bu">echo</span><spanclass="st">"text with variables. PWD=</span><spanclass="va">$PWD</span><spanclass="st">"</span></span>
<spanid="cb5-3"><ahref="#cb5-3"aria-hidden="true"tabindex="-1"></a><spanclass="bu">printf</span><spanclass="st">'%s\n'</span><spanclass="st">"text with variables. PWD=</span><spanclass="va">$PWD</span><spanclass="st">"</span></span>
<spanid="cb5-4"><ahref="#cb5-4"aria-hidden="true"tabindex="-1"></a><spanclass="ex">-</span><spanclass="op">></span> text with variables. PWD=/home/xxx</span>
<p>Use of a fixed path to the system provided bash makes it harder for attackers or users to place alternative versions of bash and avoids using a possibly broken, mangled or compromised bash executable.</p>
<p><strong>I recommend to run your bot as a user, with almost no access rights.</strong> All files your Bot have write access to are in danger to be overwritten/deleted if your bot is hacked. For the same reason every file your Bot can read is in danger to be disclosed. Restrict your Bots access rights to the absolute minimum.</p>
<p><strong>Never run your Bot as root, this is the most dangerous you can do!</strong> Usually the user 'nobody' has almost no rights on unix/linux systems. See <ahref="doc/4_expert.md">Expert use</a> on how to run your Bot as an other user.</p>
<p><strong>Your Bot configuration must no be readable from other users.</strong> Everyone who can read your Bots token is able to act as your Bot and has access to all chats the Bot is in!</p>
<p>Everyone with read access to your Bot files can extract your Bots data. Especially your Bot config in <code>config.jssh</code> must be protected against other users. No one except you should have write access to the Bot files. The Bot should be restricted to have write access to <code>count.jssh</code> and <code>data-bot-bash</code> only, all other files must be write protected.</p>
<p>To set access rights for your bashbot installation to a reasonable default run <code>sudo ./bashbot.sh init</code> after every update or change to your installation directory.</p>
<p>Bashbot is not more (in)secure as any Bot written in an other language, we have done our best to make it as secure as possible. But YOU are responsible for the bot commands you wrote and you should know about the risks ...</p>
<p><strong>Note:</strong> Up to version 0.941 (mai/22/2020) telegram-bot-bash had a remote code execution bug, please update if you use an older version!</p>
<h3>Can I have the single bashbot.sh file back?</h3>
<p>At the beginning bashbot was simply the file <code>bashbot.sh</code> you can copy everywhere and run the bot. Now we have 'commands.sh', 'mycommands.sh', 'modules/*.sh' and much more.</p>
<p>Hey no Problem, if you are finished with your cool bot run <code>dev/make-standalone.sh</code> to create a stripped down Version of your bot containing only 'bashbot.sh' and 'commands.sh'! For more information see <ahref="doc/7_develop.md">Create a stripped down Version of your Bot</a></p>
<h3>Can I send messages from CLI and scripts?</h3>
<p>Of course, you can send messages from CLI and scripts, simply install bashbot as <ahref="#Your-really-first-bashbot-in-a-nutshell">described here</a>, send the message '/start' to set yourself as botadmin and stop the bot with <code>./bashbot.sh stop</code>.</p>
<p>This may happen if to many or wrong requests are sent to api.telegram.org, e.g. using a invalid token or not existing API calls. If the block stay for longer time you can ask telegram service to unblock your IP-Adress.</p>
<p>You can check with curl or wget if you are blocked by Telegram:</p>
<spanid="cb7-2"><ahref="#cb7-2"aria-hidden="true"tabindex="-1"></a><spanclass="co">#curl: (28) Connection timed out after 10001 milliseconds</span></span>
<p>Since Version 0.96 bashbot offers the option to recover from broken connections (aka blocked). Therefore you can provide a function named <code>bashbotBlockRecover()</code> in <code>mycommands.sh</code>. If the function exists it is called every time when a broken connection is detected.</p>
<divclass="sourceCode"id="cb8"><preclass="sourceCode bash"><codeclass="sourceCode bash"><spanid="cb8-1"><ahref="#cb8-1"aria-hidden="true"tabindex="-1"></a><spanclass="co"># called when bashbot sedn command failed because we can not connect to telegram</span></span>
<spanid="cb8-2"><ahref="#cb8-2"aria-hidden="true"tabindex="-1"></a><spanclass="co"># return 0 to retry, return non 0 to give up</span></span>
<spanid="cb8-4"><ahref="#cb8-4"aria-hidden="true"tabindex="-1"></a><spanclass="co"># place your commands to unblock here, e.g. change IP-Adess or simply wait</span></span>
<spanid="cb8-5"><ahref="#cb8-5"aria-hidden="true"tabindex="-1"></a><spanclass="fu">sleep</span> 60 <spanclass="kw">&&</span><spanclass="cf">return</span><spanclass="dv">0</span><spanclass="co"># may be temporary</span></span>
