bash helper scripts, dirname/basename scripted is much much much quicker than forking a new process

gistfile1.sh

# From Shell Scripting Recipes -Chris F.A. Johnson

split_line() {
  local IFS=${DELIM:- 	}
  local opts=$-
  set -f
  RET=( $* )

  case $opts in
        *f*) ;;
        *) set +f ;;
  esac

}

strip_trailing_slashes() {
  _STRIP=$1
  while :
  do
    case $_STRIP in
      ## If the last character is a slash, remove it
      */) _STRIP=${_STRIP%/} ;;
      *) break ;;
    esac
  done
}

_basename() {
  fn_path=$1
  fn_suffix=$2
  case $fn_path in
    "") _BASENAME=; return ;;
     *)
        strip_trailing_slashes "$fn_path"
        case $_STRIP in
          "") fn_path="/" ;;
           *) fn_path=${_STRIP##*/} ;;
        esac
        ;;
  esac


  case $fn_path in
    $fn_suffix | "/" ) _BASENAME="$fn_path" ;;
                    *) _BASENAME=${fn_path%$fn_suffix} ;;
  esac
}

basename() {
  _basename "$@" && echo $_BASENAME 
}

_dirname() {
  _DIRNAME=$1
  strip_trailing_slashes "$_DIRNAME"
  case $_STRIP in
    "") _DIRNAME='/'; return ;;
   */*) _DIRNAME="${_STRIP%/*}" ;;
     *) _DIRNAME='.'; return ;;
  esac
  strip_trailing_slashes "$_DIRNAME"
  _DIRNAME=${_STRIP:-/}
}

dirname() {
  _dirname "$@" && echo $_DIRNAME
}