# return an arbitrary directory path suffix
# usage: dir_suffix num_of_path_elements [optional prefix]
function dir_suffix() {
  num=${1:-1};
  prefix=${2:-".../"}
  cd=$(pwd)
  arr=( $(echo $cd | tr '/' ' ') );
  ret="";
  len=${#arr[*]}
  if [ $len -le $num ]; then
    echo $cd
  else
    for i in $(seq $len -1 $(expr $len - $num)); do
      ret="${arr[$i]}/$ret";
    done;
    ret_len=${#ret}
    echo "${prefix}${ret:0:$(expr $ret_len - 2)}";
  fi
}

# return an abbreviated version of a path
# usage: abbr_path num_of_path_to_show [optional path]
# abbr 2 /foo/bar/baz # /f/bar/baz
function abbr_path() {
  path=${2:-$(pwd)}
  num=${1:-2}
  ret=""
  fc=${path:0:1}
  case $fc in
    "~")
      ret=$fc
      num=$(expr $num - 1)
      path=${path:1}
      ;;
    "/")
      ;;
    *)
      ret=$(expr $path : '^\([^\/]*\)\/')
      path=${path:${#ret}}
      ret=${ret:0:1}
      num=$(expr $num - 1)
      ;;
  esac
  arr=( $(echo $path | tr '[A-Z]' '[a-z]' | tr '/' ' ') )
  len=${#arr[*]}
  if [ $len -le $num ]; then
    echo ${2:-$(pwd)}
  else
    if [ $num -gt 0 ]; then
      for i in $(seq 0 1 $(expr $len - $num - 1)); do
        el=${arr[$i]}
        el=${el:0:1}
        ret="$ret/$el"
      done
    fi
    for i in $(seq $(expr $len - $num) 1 $(expr $len - 1)); do
      el=${arr[$i]}
      ret="$ret/$el"
    done
    echo "$ret/";
  fi
}