pre-commit hook that limits number of characters in a commit (including binary files)

pre-commit

#!/bin/sh

# meant to be used with husky: https://github.com/typicode/husky/blob/main/README.md
# tested on macos and ubuntu

. "$(dirname "$0")/_/husky.sh"

max_size=500000

echo "committed files:"
git diff --staged --stat HEAD # show staged diff stat
echo "" # adds \n
git diff --staged HEAD -p --text `# get staged files diff and count binary files content as text` \
  | wc -c `# count number of characters` \
  | awk -v max_size=$max_size '$1 > max_size { printf "changes (%d chars) exceeded limit of %d chars\n", $1, max_size; exit 1 }' `# fail if number of chars exceeds max_size` \
  >&2 # redirect output to stderr