Git pre-commit hook to warn about CSV, TSV, or TXT files with 50 lines or more

pre-commit.sh

#!/bin/bash

# Git pre-commit hook to warn about CSV, TSV, or TXT files with 50
# lines or more. Original example at:
#
# https://codeinthehole.com/tips/tips-for-using-a-git-pre-commit-hook/

# Make sure this script is executable. Installation is simply:
#	ln -s pre-commit.sh .git/hooks/pre-commit

FILES_PATTERN='\.(csv|tsv|txt)(\..+)?$'
FORBIDDEN='\b([5-9][0-9]|\d\d\d+)\b'
git diff --cached --name-only \
    | grep -E $FILES_PATTERN \
    | xargs wc -l \
    | grep -v -E '^\s+\d+ total$' \
    | grep --color -E $FORBIDDEN \
    && echo 'COMMIT REJECTED: files with 50 lines or longer. Please verify them before commiting.' \
    && exit 1

exit 0