I don't use a mac, and I don't have ack, and I didn't like some other things. I made it better.

git-url

#!/bin/sh
# Usage: `git url` or `git url <commitish>`
#
# * copies the commit's github url to your clipboard
# * prints out the log message
# * opens the bugzilla page if it found a bug number
#
# Assumes that the canonical remote is named upstream.
# Works on Linux

function gh_remote_url() {
    name=$1

    remote_line=$(git remote -v | grep push | grep $name)

    if [[ -z $remote_line ]]; then
        echo "Error: remote '$name' not found."
        exit 1
    fi

    if [[ ! $(echo $remote_line | grep github) ]]; then
        echo "Error: $name is not on github!"
        exit 1
    fi

    repo=$(echo $remote_line |
           sed 's/.*github.com[:\/]\([^ ]*\) .*/\1/' |
           sed 's/\.git//')

    echo "https://github.com/$repo"
}

REV=${1-HEAD}
ROOT=$(gh_remote_url upstream)
BUGZILLA='https://bugzilla.mozilla.org/show_bug.cgi?id='
HASH=$(git rev-parse $REV)
MSG=$(git log --pretty=oneline --format=%s -1 $HASH)

BUG=$(echo $MSG | grep -i 'bug [0-9]\+' | sed 's/.*bug \([0-9]\+\).*/\1/i')

echo $ROOT/$HASH | xclip
echo $MSG

# Open the browser if we found a bug number.
if [[ $BUG ]]; then
    xdg-open "${BUGZILLA}${BUG}#comment" > /dev/null
fi