Github pre-commit hook to prevent commits of large files

pre-commit

#!/bin/sh

# This is a pre-commit hook that ensures attempts to commit files that
# are larger than 100 MB to your _local_ repo fail, with a helpful error
# message.
# 
# This prevents the local repo from getting out of sync with the Github 
# repo. To install
# 1) Change this file to executable: 
#    $ chmod a+x pre-commit
# 2) Move into the .git/hooks directory at the top-level of the repo
#    $ mv pre-commit .git/hooks/
#
# See blog post on https://kiwidamien.github.io/prevent-big-commits

function file_too_large(){
	filename=$0
	# This command is more portable, but harder to reason about
	# filesize=`echo $1 | awk '{ mb =$1 / 1024 / 1024; print mb " MB"}'`
	filesize=$(( $1 / 10**6 ))

	cat <<HEREDOC
	
	File $filename is $filesize MB, which is larger than github's maximum
        file size (100 MB). We will not be able to push this file to Github.

	Commit aborted 
HEREDOC

}


empty_tree=$( git hash-object -t tree /dev/null )
limit=100000000

if git rev-parse --verify HEAD > /dev/null 2>&1
then
	against=HEAD
else
	against=empty_tree
fi

for file in $( git diff-index --cached --name-only $against ); do
	file_size=$( ls -la $file | awk '{ print $5 }')
	if [ "$file_size" -gt  "$limit" ]; then
		file_too_large $filename $file_size
		exit 1;
	fi
done

I had issues with modified files that had spaces in their name and also my cwd was different so I have it cd to the repo root straight away so the staged file paths make sense. Posted here. Got it working with Husky. Thanks for the share!

Hi Ben, Thank you for sending that! I'll update my blog post later today to include your update. Damien

…

On Thu, Nov 28, 2019 at 7:12 AM Ben McCallum ***@***.***> wrote: I had issues with modified files that had spaces in their name. I created a variation here <https://gist.github.com/benmccallum/28e4f216d9d72f5965133e6c43aaff6e> and got it working with Husky. Thanks for the share! — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <https://gist.github.com/a6a909ee196be8795b30431079074d64?email_source=notifications&email_token=AB754IKKPTAG7775P6INLADQV7NW5A5CNFSM4JSVZ6NKYY3PNVWWK3TUL52HS4DFVNDWS43UINXW23LFNZ2KUY3PNVWWK3TUL5UWJTQAF46EW#gistcomment-3095627>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AB754ILFZ6UDJI37LLH7WG3QV7NW5ANCNFSM4JSVZ6NA> .

No worries!

FYI, another fix picked up by @guysmoilov over here that's prob worth a blog update too.