Git hook to prepend ticket number to commit message

prepare-commit-msg

#!/usr/bin/env bash

# commit message file
commit_msg_file="$1"
# condition the commit is invoked; none (git commit), message (git commit -m <msg>), template, merge, squash, or commit
# commit_source=$2
# commit hash
# sha1=$3

local_branch="$(git rev-parse --abbrev-ref HEAD)"
get_ticket_nbr="^#?([0-9]{6,10}).*"
valid_ticket_nbr="^[0-9]{6,10}$"

error() 
{
    echo "GIT PREPARE-COMMIT HOOK ERROR:"
    echo "$1"
    echo ""

    exit 1
}


# check if commit message already has the ticket # prepended
# if not, try to prepend
commit_msg=$(cat "$commit_msg_file")
if [[ ! $commit_msg =~ $get_ticket_nbr ]]
then
    if [[ $local_branch =~ $get_ticket_nbr ]]
    then
        ticket="${BASH_REMATCH[1]}"
        if [[ $ticket =~ $valid_ticket_nbr ]]
        then
            echo "#${ticket} " > "$commit_msg_file"
            echo "$commit_msg" >> "$commit_msg_file"
        fi
    fi
fi

exit 0