pre-commit hook to prevent large file on git commit (and allow git-lfs tracked binary files to pass through)

pre-commit

#!/bin/sh
#
# An example hook script to verify what is about to be committed.
# Called by "git commit" with no arguments. The hook should
# exit with non-zero status after issuing an appropriate message if
# it wants to stop the commit.
#
# To enable this hook, rename this file to "pre-commit".

# Redirect output to stderr.
exec 1>&2

FILE_SIZE_LIMIT_KB=1024
CURRENT_DIR="$(pwd)"
COLOR='\033[01;33m'
NOCOLOR='\033[0m'
HAS_ERROR=""
COUNTER=0

# generate file extension filter from gitattributes for git-lfs tracked files
filter=$(cat .gitattributes | grep filter=lfs | awk '{printf "-e .%s$ ", $1}')

# before git commit, check non git-lfs tracked files to limit size
files=$(git diff --cached --name-only | sort | uniq | grep -v $filter)
while read -r file; do
	if [ "$file" = "" ]; then
		continue
	fi
	file_path=$CURRENT_DIR/$file
	file_size=$(ls -l "$file_path" | awk '{print $5}')
	file_size_kb=$((file_size / 1024))
	if [ "$file_size_kb" -ge "$FILE_SIZE_LIMIT_KB" ]; then
		echo "${COLOR}${file}${NOCOLOR} has size ${file_size_kb}KB, over commit limit ${FILE_SIZE_LIMIT_KB}KB."
		HAS_ERROR="YES"
		((COUNTER++))
	fi
done <<< "$files"

# exit with error if any non-lfs tracked files are over file size limit
if [ "$HAS_ERROR" != "" ]; then
	echo "$COUNTER files are larger than permitted, please fix them before commit" >&2
	exit 1
fi

exit 0

on GNU/Linux, I switch to #!/bin/bash (because of the <<< at line 37), and to echo -e.

If there is a space in username, there is a problem when retrieving the file size.
Line 30 can be replace by file_size=$(stat --printf="%s" "$file_path")

And to avoiding testing deleted file Line 24 can be replace by files=$(git diff --cached --name-only --diff-filter=d | sort | uniq | grep -v $filter)

Instead of manually parsing .gitattributes, there is also git check-attr, which is less error prone to use and also works with bare repositories.