scripts/rellns-sh

   1 #!/bin/sh
   2 # rellns-sh - Simplified ln program to generate relative symbolic link.
   3 # Copyright (C) 1996-2023 Free Software Foundation, Inc.
   4 #
   5 # This program is free software; you can redistribute it and/or modify
   6 # it under the terms of the GNU General Public License as published by
   7 # the Free Software Foundation; either version 2, or (at your option)
   8 # any later version.
   9 #
  10 # This program is distributed in the hope that it will be useful,
  11 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 # GNU General Public License for more details.
  14 #
  15 # You should have received a copy of the GNU General Public License
  16 # along with this program; if not, see <https://www.gnu.org/licenses/>.
  17
  18 # With -p, instead of creating the link print the computed relative link
  19 # name.
  20 do_print=false
  21 case $1 in
  22   -p)
  23     do_print=true
  24     shift
  25     ;;
  26 esac
  27 if test $# -ne 2; then
  28   echo "Usage: rellns [-p] SOURCE DEST" >&2
  29   exit 1
  30 fi
  31
  32 # Make both paths absolute.
  33 if test -d $1; then
  34   to=`cd $1 && pwd -P`
  35 else
  36   temp=`echo $1 | sed 's%/*[^/]*$%%'`
  37   if test -z "$temp"; then
  38     to=`pwd -P`
  39   else
  40     to=`cd $temp && pwd -P`
  41   fi
  42   to="$to/`echo $1 | sed 's%.*/\([^/][^/]*\)$%\1%'`"
  43 fi
  44 to=`echo $to | sed 's%^/%%'`
  45
  46 if test -d $2; then
  47   from=`echo $2 | sed 's%/*$%%'`
  48 else
  49   from=`echo $2 | sed 's%/*[^/]*$%%'`
  50 fi
  51
  52 if test -z "$from"; then
  53   from=`pwd -P | sed 's%^/%%'`
  54 else
  55   from=`cd $from && pwd -P | sed 's%^/%%'`
  56 fi
  57
  58 while test -n "$to" && test -n "$from"; do
  59   preto=`echo $to | sed 's%^\([^/]*\)/.*%\1%'`
  60   prefrom=`echo $from | sed 's%^\([^/]*\)/.*%\1%'`
  61
  62   test "$preto" != "$prefrom" && break
  63
  64   to=`echo $to | sed 's%^[^/]*/*\(.*\)$%\1%'`
  65   from=`echo $from | sed 's%^[^/]*/*\(.*\)$%\1%'`
  66 done
  67
  68 while test -n "$from"; do
  69   rfrom="../$rfrom"
  70   from=`echo $from | sed 's%^[^/]*/*%%'`
  71 done
  72
  73 if $do_print; then
  74   echo "$rfrom$to"
  75 else
  76   ln -s $rfrom$to $2
  77 fi