bashrc

function traildir()
{
    local n=$1 dir=$2
    local sl tildedir homelen shifted  traildir
    local oldifs=$IFS

    tildedir=${dir#$HOME}
    if ! [[ "$tildedir" == "$dir" ]]; then
            # Special break out case
            [[ -z "$tildedir" ]] && { echo "~"; return 0; }

            sl="~/"
    else
            sl="/"
    fi

    set -- ${HOME//\// }
    homelen=$#

    shifted=0
    IFS="/"
    set -- ${tildedir/\//}
    if [[ $# -gt $n ]]; then
            shifted=$(($# - $n))
            shift $shifted
            traildir="$sl<$shifted>/$*"
    else
            traildir="$sl$*"
    fi

    IFS=$oldifs
    echo $traildir
}