iankelling.org Git - distro-setup/blob - path_add-function

   1 #!/bin/bash
   2 # avoiding bashisms so it can be used in edge cases where I don't have bash,
   3 # however, I'm not super confident that I've avoided them all
   4 #
   5 #
   6 path_add() {
   7     local help="usage: path_add [options] PATH
   8 --help:     print this
   9 --end:      adds to end of path, which will give it lowest priority
  10 --ifexists: add to path only if the directory exists"
  11     local found x y z ifexists end loop newpath
  12     ifexists=false
  13     end=false
  14     loop=true
  15     # portable substring matching is ugly http://mywiki.wooledge.org/BashFAQ/041
  16     while $loop; do
  17         case $1 in
  18             --*)
  19                 if [ "$1" = --end ]; then
  20                     end=true
  21                 elif [ "$1" = --ifexists ]; then
  22                     ifexists=true
  23                 elif [ "$1" = --help ]; then
  24                     echo "$help"
  25                     return
  26                 fi
  27                 shift
  28                 ;;
  29             *)
  30                 loop=false
  31                 ;;
  32         esac
  33     done
  34     IFS=:
  35     # build up the path without the components we want to add
  36     for y in $PATH; do
  37         for x in "$@"; do
  38             if [ "$x" = "$y" ]; then
  39                 found=true
  40             else
  41                 found=false
  42             fi
  43         done
  44         if ! $found; then
  45             if [ ! "$newpath" ]; then
  46                 newpath="$y"
  47             else
  48                 newpath="$newpath:$y"
  49             fi
  50         fi
  51     done
  52
  53     unset IFS
  54     PATH="$newpath"
  55     for x in "$@"; do
  56         if ! $ifexists || [ -d "$x" ]; then
  57             if [ ! "$PATH" ]; then
  58                 PATH="$x"
  59             elif $end; then
  60                 PATH="$PATH:$x"
  61             else
  62                 PATH="$x:$PATH"
  63             fi
  64         fi
  65     done
  66 }