post-receive

#!/bin/sh

# Alternative to the pre-push hook, this one can be used to automatically update
# `master` whenever `main` changes.
#
# See: https://github.com/wincent/wincent/issues/100

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

while read OLD_REV NEW_REV REF_NAME; do
  if [ "$NEW_REV" = "$ZERO" ]; then
    # Branch was deleted. We dare not tread here.
    :
  elif [ "$REF_NAME" = "refs/heads/main" ]; then
    git branch -f master "$NEW_REV"
  fi
done