qpdf: selecting --keep-open-files=y
qpdf: processing 20-pages.pdf
qpdf: processing ./20-pages.pdf
qpdf: processing minimal.pdf
qpdf: ./20-pages.pdf: checking for shared resources
qpdf: no shared resources found
qpdf: 20-pages.pdf: checking for shared resources
qpdf: no shared resources found
qpdf: minimal.pdf: checking for shared resources
qpdf: no shared resources found
qpdf: page-labels-and-outlines.pdf: checking for shared resources
qpdf: no shared resources found
qpdf: removing unreferenced pages from primary input
qpdf: adding pages from page-labels-and-outlines.pdf
qpdf: adding pages from 20-pages.pdf
qpdf: adding pages from page-labels-and-outlines.pdf
qpdf: adding pages from 20-pages.pdf
qpdf: adding pages from ./20-pages.pdf
qpdf: adding pages from minimal.pdf
qpdf: a.pdf: write progress: 0%
....other write progress....
qpdf: a.pdf: write progress: 100%
qpdf: wrote file a.pdf
