1#!/bin/sh
2# rellns-sh - Simplified ln program to generate relative symbolic link.
3# Copyright (C) 1996-2022 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.
20do_print=false
21case $1 in
22  -p)
23    do_print=true
24    shift
25    ;;
26esac
27if test $# -ne 2; then
28  echo "Usage: rellns [-p] SOURCE DEST" >&2
29  exit 1
30fi
31
32# Make both paths absolute.
33if test -d $1; then
34  to=`cd $1 && pwd -P`
35else
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%'`"
43fi
44to=`echo $to | sed 's%^/%%'`
45
46if test -d $2; then
47  from=`echo $2 | sed 's%/*$%%'`
48else
49  from=`echo $2 | sed 's%/*[^/]*$%%'`
50fi
51
52if test -z "$from"; then
53  from=`pwd -P | sed 's%^/%%'`
54else
55  from=`cd $from && pwd -P | sed 's%^/%%'`
56fi
57
58while test -n "$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%^[^/]*/*\(.*\)$%\1%'`
66done
67
68while test -n "$from"; do
69  rfrom="../$rfrom"
70  from=`echo $from | sed 's%^[^/]*/*%%'`
71done
72
73if $do_print; then
74  echo "$rfrom$to"
75else
76  ln -s $rfrom$to $2
77fi
78