Shell script functions to replace basename and dirname

When writing shell-scripts, it is quite common to use the basename and dirname. Since they are typically provided as shell scripts under /usr/bin/, I wrote my own set of the as Bash functions instead. Feel free to use them as you see fit.

function basename () {
    if [ $# -lt 1 ]; then
        echo "Usage: $0  [  ]" 1>&2
        return 1
    else
        local -r sfx=${2-''}
        local -r trim=${1%/}
        local -r fname=${trim##*/}
        echo ${fname%%$sfx}
        return 0
    fi
}

function dirname () {
    if [ $# -lt 1 ]; then
        echo "Usage: $0 " 1>&2
        return 1
    else
        local -r fname=${1%/?*}
        if [ "x$fname" = "x$1" ]; then
            echo "."
        else
            echo $fname
        fi
        return 0
    fi
}