Ticket number prefix without branch (reads .ticket file)

commit-msg.php

#!/usr/bin/php
# FILE: .git/hooks/commit-msg
<?php

$commitMessages = file($argv[1]);

if (preg_match('(^[0-9]+:\s*$)', $commitMessages[0])) {
    echo "Empty commit message, aborting.\n";
    exit(1);
}

prepare-commit-msg.php

#!/usr/bin/php
# FILE: .git/hooks/prepare-commit-msg
<?php

if (isset($argv[2])) {
    echo "Special commit type. Won't edit message.\n";
    exit(0);
}

if (!file_exists('.ticket')) {
    echo "No .ticket file found. Won't edit message.\n";
    exit(0);
}

$commitFile = $argv[1];
$ticketNumber = trim(file_get_contents('.ticket'));

if ($ticketNumber === '') {
    echo "No ticket number in ticket file. Won't edit message.\n";
    exit(0);
}

file_put_contents(
    $commitFile,
    $ticketNumber . ': ' . file_get_contents($commitFile)
);

echo "Prefixed commit message with ticket number {$ticketNumber}.\n";
exit(0);

git config --global core.editor "vim '+ normal \$'" makes your VIM start at the end of the line (aka behind the ticket number) for editing the commit message.