qpdf Cheat Sheet & Reference

Obsidian Metadata

date	2026-09-14
published	2026-09-14

QPDF — practical reference

Setup on macOS

With Homebrew installed:

brew install qpdf
qpdf --version

Open Terminal and move into the folder containing your PDFs:

cd ~/Downloads

My working convention

Keep the original. Give outputs descriptive names such as statement-unlocked.pdf or report-selected.pdf. Quote filenames containing spaces. Replace example filenames before running commands.

Everyday commands

These recipes follow the official QPDF command reference.

Remove a known password

qpdf --password='YOUR_PASSWORD' --decrypt "locked.pdf" "unlocked.pdf"

For sensitive passwords, use a local file containing the password on its first line:

qpdf --password-file="password.txt" --decrypt "locked.pdf" "unlocked.pdf"

Password handling

Literal passwords can remain in shell history. Keep password files and unlocked documents out of shared folders and your Obsidian vault; delete the temporary password file afterward.

Merge PDFs

qpdf --empty --pages "first.pdf" "second.pdf" -- "merged.pdf"

Extract or reorder pages

qpdf "input.pdf" --pages . 2-5 -- "extract.pdf"
qpdf "input.pdf" --pages . 3,1,2,4-z -- "reordered.pdf"

Pages start at 1; z means last page; . means the input. The closing -- ends page selection.

Remove page 3

qpdf "input.pdf" --pages . 1-2,4-z -- "without-page-3.pdf"

Split into individual pages

qpdf "input.pdf" --split-pages "page.pdf"

Rotate all pages clockwise

qpdf "input.pdf" --rotate=+90:1-z "rotated.pdf"

Try lossless compression

qpdf "input.pdf" --object-streams=generate --recompress-flate --compression-level=9 "smaller.pdf"

Savings vary; compare sizes.

Check structure or count pages

qpdf --check "input.pdf"
qpdf --show-npages "input.pdf"

Ordinary exit codes: 0 success, 2 error, 3 warnings. A structural check does not guarantee correct rendering.

Help

qpdf --help
qpdf --help=--pages

Before using the result

• Open the output and inspect the relevant pages.

• Confirm page order and that the expected content is present.

• For a merged report, inspect bookmarks and forms if you rely on them.

• Keep a separate original of any digitally signed document.

Personal examples to add later

• Most frequent task:

• Folder where I keep source PDFs:

• Command that worked: