scripts/rellns-sh

   1 #! /bin/sh
   2 # rellns-sh - Simplified ln program to generate relative symbolic link.
   3 # Copyright (C) 1996-2015 Free Software Foundation, Inc.
   4 # Written by Ulrich Drepper <drepper@cygnus.com>, October 1996
   5 #
   6 # This program is free software; you can redistribute it and/or modify
   7 # it under the terms of the GNU General Public License as published by
   8 # the Free Software Foundation; either version 2, or (at your option)
   9 # any later version.
  10 #
  11 # This program is distributed in the hope that it will be useful,
  12 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 # GNU General Public License for more details.
  15 #
  16 # You should have received a copy of the GNU General Public License
  17 # along with this program; if not, see <http://www.gnu.org/licenses/>.
  18
  19 # With -p, instead of creating the link print the computed relative link
  20 # name.
  21 do_print=false
  22 case $1 in
  23   -p)
  24     do_print=true
  25     shift
  26     ;;
  27 esac
  28 if test $# -ne 2; then
  29   echo "Usage: rellns [-p] SOURCE DEST" >&2
  30   exit 1
  31 fi
  32
  33 if test -x /bin/pwd; then
  34   pwd=/bin/pwd
  35 elif test -x /usr/bin/pwd; then
  36   pwd=/usr/bin/pwd
  37 else
  38   pwd='pwd'
  39 fi
  40
  41 # Make both paths absolute.
  42 if test -d $1; then
  43   to=`cd $1 && $pwd`
  44 else
  45   temp=`echo $1 | sed 's%/*[^/]*$%%'`
  46   if test -z "$temp"; then
  47     to=`$pwd`
  48   else
  49     to=`cd $temp && $pwd`
  50   fi
  51   to="$to/`echo $1 | sed 's%.*/\([^/][^/]*\)$%\1%'`"
  52 fi
  53 to=`echo $to | sed 's%^/%%'`
  54
  55 if test -d $2; then
  56   from=`echo $2 | sed 's%/*$%%'`
  57 else
  58   from=`echo $2 | sed 's%/*[^/]*$%%'`
  59 fi
  60
  61 if test -z "$from"; then
  62   from=`$pwd | sed 's%^/%%'`
  63 else
  64   from=`cd $from && $pwd | sed 's%^/%%'`
  65 fi
  66
  67 while test -n "$to" && test -n "$from"; do
  68   preto=`echo $to | sed 's%^\([^/]*\)/.*%\1%'`
  69   prefrom=`echo $from | sed 's%^\([^/]*\)/.*%\1%'`
  70
  71   test "$preto" != "$prefrom" && break
  72
  73   to=`echo $to | sed 's%^[^/]*/*\(.*\)$%\1%'`
  74   from=`echo $from | sed 's%^[^/]*/*\(.*\)$%\1%'`
  75 done
  76
  77 while test -n "$from"; do
  78   rfrom="../$rfrom"
  79   from=`echo $from | sed 's%^[^/]*/*%%'`
  80 done
  81
  82 if $do_print; then
  83   echo "$rfrom$to"
  84 else
  85   ln -s $rfrom$to $2
  86 fi