Batch-crop screenshots by a fixed pixel inset per side — the same amount on three sides, a larger one on top — writing the results to a trimmed/ subdirectory.

grimshot save window (bound to Ctrl+Print, see sway/keybindings) captures the whole window node, chrome included. For a QEMU VM window that means two bands you never want in a document: sway’s frame all the way round, and the VM’s own GTK menubar along the top. shot-trim removes both in one pass over a batch and never touches the originals.

Run it

shot-trim ~/Screenshots/2026-08-23T12*.png

Each file is cropped and written to <its dir>/trimmed/<same name>; one line per file, then a summary:

$ cd ~/Screenshots && shot-trim 2026-08-23T12*.png
2026-08-23T12:05:12,251788794+02:00.png  1222x880 -> 1212x843
2026-08-23T12:25:46,613768577+02:00.png  1201x979 -> 1191x942
22 trimmed, 0 skipped, 0 failed

Check before committing to it with -n (dry run: prints the same lines plus the destination path, writes nothing).

Why the defaults are 5 and 32

So: 5 px left/right/bottom, and 5 + 27 = 32 px top. If default_border changes, the side defaults in the script have to change with it — nothing detects the frame at run time, by design (a fixed inset gives every shot in a batch the same size, which matters when they get stacked in a document).

Options

shot-trim [-l N] [-r N] [-b N] [-t N] [-o DIR] [-n] FILE...

  -l N    left inset, px          (default 5)
  -r N    right inset, px         (default 5)
  -b N    bottom inset, px        (default 5)
  -t N    top inset, px           (default 32)
  -o DIR  output directory        (default: <dir of each input>/trimmed)
  -n      dry run
  -h      help

Exit status: 0 everything trimmed · 1 usage or dependency error · 2 some files were skipped or failed.

• A capture without the VM menubar (an area grab, say): shot-trim -t 5 shot.png.
• Collect a mixed batch in one place: shot-trim -o ~/doc-figures *.png.

Without the script

The operation itself is one ImageMagick call, if you’d rather not install anything:

mkdir -p trimmed && mogrify -path trimmed -shave 5x5 -gravity North -chop 0x27 +repage *.png

-shave 5x5 takes 5 px off all four sides, -chop 0x27 takes the menubar off the top. The script exists for the guards below, not for the crop.

Robustness invariants

• Temp file, then mv. Every output is written to .shot-trim.XXXXXX in the destination directory and moved into place, so a failed or interrupted magick can never leave a truncated PNG at the real path. The EXIT trap sweeps the temp files; verified with a stubbed magick that fails, and with a Ctrl-C mid-crop (exit 130, no leftovers).
• +repage is not optional. Without it the crop offset is recorded in the PNG and downstream tools inherit a +5+32 page geometry.
• png: on the writer. The output format comes from the coder prefix, never from the temp file’s name.
• Inputs are never outputs. A file already sitting in a trimmed/ directory is skipped (it has been cropped once already; pass -o to crop it again on purpose), and so is any file whose directory is the -o destination — that case would overwrite the original.
• grimshot filenames contain colons (2026-08-23T12:25:46,…). ImageMagick reads a prefix: as a coder name, but falls back to treating the whole string as a path when no coder matches — 2026-08-23T12 never will. Verified across the folder.
• Insets that would leave nothing (-t 500 on a 468 px-tall shot) are reported as a skip, not passed to ImageMagick.

Known limitations

• PNG only. Non-.png inputs are skipped, since the writer forces png:.
• Fixed insets, no detection. Deliberate — see above.
• No single-instance lock and no notify-send: this is a terminal tool, not a keybinding (see the deviations noted in the script header and dev/authoring-shell-utilities §0, §7.2).