prepare-commit-msg

#!/bin/sh

COMMIT_MSG_FILE=$1  # The git commit file.
COMMIT_SOURCE=$2    # The current commit message.

# Add "Signed-off-by: <user> <email>" to every commit message.
SOB=$(git var GIT_COMMITTER_IDENT | sed -n 's/^\(.*>\).*$/Signed-off-by: \1/p')
git interpret-trailers --in-place --trailer "$SOB" "$COMMIT_MSG_FILE"
if test -z "$COMMIT_SOURCE"; then
  /usr/bin/perl -i.bak -pe 'print "\n" if !$first_line++' "$COMMIT_MSG_FILE"
fi