function xmap() {
    # Run a shell command once for every argument passed. The first argument
    # should be a single-quoted string appropriate to pass to  sh -c.
    # For example:
    #       % xmap 'echo @' foo bar baz
    #       echo foo
    #       echo bar
    #       echo baz

    cmd=$1
    shift

    echo -n ${@} | xargs -r -d" " -I@ sh -c "${cmd}"
}