examples/functions/whence

   1 #
   2 # An almost-ksh compatible `whence' command.  This is as hairy as it is
   3 # because of the desire to exactly mimic ksh.
   4 #
   5 # This depends somewhat on knowing the format of the output of the bash
   6 # `builtin type' command.
   7 #
   8 # Chet Ramey
   9 # chet@ins.CWRU.Edu
  10 #
  11 whence()
  12 {
  13         local vflag= path=
  14
  15         if [ "$#" = "0" ] ; then
  16                 echo "whence: argument expected"
  17                 return 1
  18         fi
  19         case "$1" in
  20                 -v) vflag=1
  21                     shift 1
  22                     ;;
  23                 -*) echo "whence: bad option: $1"
  24                     return 1
  25                     ;;
  26                  *) ;;
  27         esac
  28
  29         if [ "$#" = "0" ] ; then
  30                 echo "whence: bad argument count"
  31                 return 1
  32         fi
  33
  34         for cmd
  35         do
  36                 if [ "$vflag" ]  ; then
  37                         echo $(builtin type $cmd | sed 1q)
  38                 else
  39                         path=$(builtin type -path $cmd)
  40                         if [ "$path" ] ; then
  41                                 echo $path
  42                         else
  43                                 case "$cmd" in
  44                                         /*) if [ -x "$cmd" ]; then
  45                                                 echo "$cmd"
  46                                             fi
  47                                             ;;
  48                                          *) case "$(builtin type -type $cmd)" in
  49                                                 "") ;;
  50                                                  *) echo "$cmd"
  51                                                     ;;
  52                                             esac
  53                                             ;;
  54                                 esac
  55                         fi
  56                 fi
  57         done
  58         return 0
  59 }