scripts/rellns-sh

   1 #!/bin/sh
   2 # rellns-sh - Simplified ln program to generate relative symbolic link.
   3 # Copyright (C) 1996-2020 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 <https://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 # Make both paths absolute.
  34 if test -d $1; then
  35   to=`cd $1 && pwd -P`
  36 else
  37   temp=`echo $1 | sed 's%/*[^/]*$%%'`
  38   if test -z "$temp"; then
  39     to=`pwd -P`
  40   else
  41     to=`cd $temp && pwd -P`
  42   fi
  43   to="$to/`echo $1 | sed 's%.*/\([^/][^/]*\)$%\1%'`"
  44 fi
  45 to=`echo $to | sed 's%^/%%'`
  46
  47 if test -d $2; then
  48   from=`echo $2 | sed 's%/*$%%'`
  49 else
  50   from=`echo $2 | sed 's%/*[^/]*$%%'`
  51 fi
  52
  53 if test -z "$from"; then
  54   from=`pwd -P | sed 's%^/%%'`
  55 else
  56   from=`cd $from && pwd -P | sed 's%^/%%'`
  57 fi
  58
  59 while test -n "$to" && test -n "$from"; do
  60   preto=`echo $to | sed 's%^\([^/]*\)/.*%\1%'`
  61   prefrom=`echo $from | sed 's%^\([^/]*\)/.*%\1%'`
  62
  63   test "$preto" != "$prefrom" && break
  64
  65   to=`echo $to | sed 's%^[^/]*/*\(.*\)$%\1%'`
  66   from=`echo $from | sed 's%^[^/]*/*\(.*\)$%\1%'`
  67 done
  68
  69 while test -n "$from"; do
  70   rfrom="../$rfrom"
  71   from=`echo $from | sed 's%^[^/]*/*%%'`
  72 done
  73
  74 if $do_print; then
  75   echo "$rfrom$to"
  76 else
  77   ln -s $rfrom$to $2
  78 fi