Make Mac friendly

prepare-commit-msg

#!/bin/sh
#
# An example hook script to prepare the commit log message.
# Called by "git commit" with the name of the file that has the
# commit message, followed by the description of the commit
# message's source.  The hook's purpose is to edit the commit
# message file.  If the hook fails with a non-zero status,
# the commit is aborted.
#
# To enable this hook, rename this file to "prepare-commit-msg" and
# place it in .git/hooks.
#
# To enable this for all git projects uses the global configuration
# 'init.templatedir'. Create a directory for git templates and a 
# subdirectory for hooks.
# > mkdir -p ~/.git_template/hooks
# Use the following command to configure this as your git templates 
# directory.
# > git config --global init.templatedir '~/.git_template'
#
# Now when you init a new git repo, the hook directory along with
# any hooks will automatically be placed in the new project git
# repo.
#
# You can also run 'git init' on an existing repo to have the
# reinitialized with the latest templates.
#
# Exit status of non zero will lead to a failed commit.

# Get the name of the branch in the current working tree.
NAME=$(git symbolic-ref -q --short HEAD)

# Check the branch name for a 5 to 7 digit number (an issue number).
if [ `uname -s` = 'Darwin' ]
then
    ISSUE_NUMBER=`expr "$NAME" : '\([0-9]*\)'`
else
    ISSUE_NUMBER=`expr match "$NAME" '\([0-9]\{5,7\}\)'`
fi

# If branch contains a match for an issue number prepend the commit
# message with 'Ref <issue_number> <commit message>.
if [ -n "$ISSUE_NUMBER" ]
then
    OLD_IFS=$IFS
    IFS=''
    echo "Ref $ISSUE_NUMBER\n"$(cat "$1") > "$1"
    IFS=$OLD_IFS
fi