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 bush
   6 # `builtin type' command.
   7 #
   8 # Chet Ramey
   9 # chet@ins.CWRU.Edu
  10 #
  11 #
  12 #  Chet Ramey <chet.ramey@case.edu>
  13 #
  14 #  Copyright 1994 Chester Ramey
  15 #
  16 #   This program is free software; you can redistribute it and/or modify
  17 #   it under the terms of the GNU General Public License as published by
  18 #   the Free Software Foundation; either version 2, or (at your option)
  19 #   any later version.
  20 #
  21 #   TThis program is distributed in the hope that it will be useful,
  22 #   but WITHOUT ANY WARRANTY; without even the implied warranty of
  23 #   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  24 #   GNU General Public License for more details.
  25 #
  26 #   You should have received a copy of the GNU General Public License
  27 #   along with this program; if not, write to the Free Software Foundation,
  28 #   Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  29
  30 whence()
  31 {
  32         local vflag= path=
  33
  34         if [ "$#" = "0" ] ; then
  35                 echo "whence: argument expected"
  36                 return 1
  37         fi
  38         case "$1" in
  39                 -v) vflag=1
  40                     shift 1
  41                     ;;
  42                 -*) echo "whence: bad option: $1"
  43                     return 1
  44                     ;;
  45                  *) ;;
  46         esac
  47
  48         if [ "$#" = "0" ] ; then
  49                 echo "whence: bad argument count"
  50                 return 1
  51         fi
  52
  53         for cmd
  54         do
  55                 if [ "$vflag" ]  ; then
  56                         echo $(builtin type $cmd | sed 1q)
  57                 else
  58                         path=$(builtin type -path $cmd)
  59                         if [ "$path" ] ; then
  60                                 echo $path
  61                         else
  62                                 case "$cmd" in
  63                                         /*) if [ -x "$cmd" ]; then
  64                                                 echo "$cmd"
  65                                             fi
  66                                             ;;
  67                                          *) case "$(builtin type -type $cmd)" in
  68                                                 "") ;;
  69                                                  *) echo "$cmd"
  70                                                     ;;
  71                                             esac
  72                                             ;;
  73                                 esac
  74                         fi
  75                 fi
  76         done
  77         return 0
  78 }