git-branch-status

#!/usr/bin/env bash

# Usage: git-branch-status
# Show how many commits each branch is ahead or behind its upstream.

branch=`git rev-parse --abbrev-ref HEAD`

git for-each-ref --format='%(refname:short) %(upstream:short)' refs/heads | \
while read local upstream; do

    # Use master if upstream branch is empty
    [ -z $upstream ] && upstream=master

    ahead=`git rev-list ${upstream}..${local} --count`
    behind=`git rev-list ${local}..${upstream} --count`

    if [[ $local == $branch ]]; then
        asterisk=*
    else
        asterisk=' '
    fi

    # Show asterisk before current branch
    echo -n "$asterisk $local"

    # Does this branch is ahead or behind upstream branch?
    if [[ $ahead -ne 0 && $behind -ne 0 ]]; then
        echo -n " ($ahead ahead and $behind behind $upstream)"
    elif [[ $ahead -ne 0 ]]; then
        echo -n " ($ahead ahead $upstream)"
    elif [[ $behind -ne 0 ]]; then
        echo -n " ($behind behind $upstream)"
    fi

    # Newline
    echo

done;