#!/bin/sh

# This script assume that you have your bare repositories below this directory :
REPOS_ROOT=/var/git/

error()
{
    echo "git-gc: error: $1."
}

run()
{
    if [ -d "$REPOS_ROOT" ] ; then
        find "$REPOS_ROOT" -mindepth 1 -maxdepth 1 -type d -print0 |
            xargs -0 -Ipath su www-data -c "git --git-dir='path' gc"
    return 0
    fi

    error "$REPOS_ROOT doesn't exists"
    return 1
}

run

exit $?