pre-push git hook to generate changelog file

pre-push

#!/bin/sh

# Save input for use in git lfs and for changelog generation.
stdin_input=`cat`

command -v git-lfs >/dev/null 2>&1 || { echo >&2 "\nThis repository is configured for Git LFS but 'git-lfs' was not found on your path. If you no longer wish to use Git LFS, remove this hook by deleting the 'pre-push' file in the hooks directory (set by 'core.hookspath'; usually '.git/hooks').\n"; exit 2; }
echo "$stdin_input" | git lfs pre-push "$@"

zero=$(git hash-object --stdin </dev/null | tr '[0-9a-f]' '0')

echo "Handling pre-push"

echo "$stdin_input" | while read local_ref local_oid remote_ref remote_oid
do
    if test "$local_oid" = "$zero"
    then
        # Handle delete
        :
    else
        changelog_file="changelog/$(git branch --show-current | tr '/' '.').txt"
        # Only create the file if it doesn't exist.
        if [ ! -f "$changelog_file" ]
        then
            echo "🐛🕶⭐⛳️ $(git log main.. --format=format:%s)" > $changelog_file
        else 
            echo "Not overwriting existing changelog file"
        fi
    fi
done