ossp-pkg/shtool/sh.mkln
##
## mkln -- Make link with calculation of relative paths
## Copyright (c) 1998-2008 Ralf S. Engelschall <rse@engelschall.com>
##
## This file is part of shtool and free software; you can redistribute
## it and/or modify it under the terms of the GNU General Public
## License as published by the Free Software Foundation; either version
## 2 of the License, or (at your option) any later version.
##
## This file is distributed in the hope that it will be useful,
## but WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
## General Public License for more details.
##
## You should have received a copy of the GNU General Public License
## along with this program; if not, write to the Free Software
## Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
## USA, or contact Ralf S. Engelschall <rse@engelschall.com>.
##
str_tool="mkln"
str_usage="[-t|--trace] [-f|--force] [-s|--symbolic] <src-path> [<src-path> ...] <dst-path>"
arg_spec="2+"
opt_spec="t.f.s."
opt_alias="t:trace,f:force,s:symbolic"
opt_t=no
opt_f=no
opt_s=no
. ./sh.common
# determine source(s) and destination
args=$#
srcs=""
while [ $# -gt 1 ]; do
srcs="$srcs $1"
shift
done
dst="$1"
if [ ! -d $dst ]; then
if [ $args -gt 2 ]; then
echo "$msgprefix:Error: multiple sources not allowed when target isn't a directory" 1>&2
shtool_exit 1
fi
fi
# determine link options
lnopt=""
if [ ".$opt_f" = .yes ]; then
lnopt="$lnopt -f"
fi
if [ ".$opt_s" = .yes ]; then
lnopt="$lnopt -s"
fi
# iterate over sources
for src in $srcs; do
# determine if one of the paths is an absolute path,
# because then we _have_ to use an absolute symlink
oneisabs=0
srcisabs=0
dstisabs=0
case $src in
/* ) oneisabs=1; srcisabs=1 ;;
esac
case $dst in
/* ) oneisabs=1; dstisabs=1 ;;
esac
# split source and destination into dir and base name
if [ -d $src ]; then
srcdir=`echo $src | sed -e 's;/*$;;'`
srcbase=""
else
srcdir=`echo $src | sed -e 's;^[^/]*$;;' -e 's;^\(.*/\)[^/]*$;\1;' -e 's;\(.\)/$;\1;'`
srcbase=`echo $src | sed -e 's;.*/\([^/]*\)$;\1;'`
fi
if [ -d $dst ]; then
dstdir=`echo $dst | sed -e 's;/*$;;'`
dstbase=""
else
dstdir=`echo $dst | sed -e 's;^[^/]*$;;' -e 's;^\(.*/\)[^/]*$;\1;' -e 's;\(.\)/$;\1;'`
dstbase=`echo $dst | sed -e 's;.*/\([^/]*\)$;\1;'`
fi
# consistency check
if [ ".$dstdir" != . ]; then
if [ ! -d $dstdir ]; then
echo "$msgprefix:Error: destination directory not found: $dstdir" 1>&2
shtool_exit 1
fi
fi
# make sure the source is reachable from the destination
if [ $dstisabs = 1 ]; then
if [ $srcisabs = 0 ]; then
if [ ".$srcdir" = . ]; then
srcdir="`pwd | sed -e 's;/*$;;'`"
srcisabs=1
oneisabs=1
elif [ -d $srcdir ]; then
srcdir="`cd $srcdir; pwd | sed -e 's;/*$;;'`"
srcisabs=1
oneisabs=1
fi
fi
fi
# split away a common prefix
prefix=""
if [ ".$srcdir" = ".$dstdir" ] && [ ".$srcdir" != . ]; then
prefix="$srcdir/"
srcdir=""
dstdir=""
else
while [ ".$srcdir" != . ] && [ ".$dstdir" != . ]; do
presrc=`echo $srcdir | sed -e 's;^\([^/][^/]*\)/.*;\1;'`
predst=`echo $dstdir | sed -e 's;^\([^/][^/]*\)/.*;\1;'`
if [ ".$presrc" != ".$predst" ]; then
break
fi
prefix="$prefix$presrc/"
srcdir=`echo $srcdir | sed -e 's;^[^/][^/]*/*;;'`
dstdir=`echo $dstdir | sed -e 's;^[^/][^/]*/*;;'`
done
fi
# destination prefix is just the common prefix
dstpre="$prefix"
# determine source prefix which is the reverse directory
# step-up corresponding to the destination directory
srcpre=""
allow_relative_srcpre=no
if [ ".$prefix" != . ] && [ ".$prefix" != ./ ]; then
allow_relative_srcpre=yes
fi
if [ $oneisabs = 0 ]; then
allow_relative_srcpre=yes
fi
if [ ".$opt_s" != .yes ]; then
allow_relative_srcpre=no
fi
if [ ".$allow_relative_srcpre" = .yes ]; then
pl="$dstdir/"
OIFS="$IFS"; IFS='/'
for pe in $pl; do
[ ".$pe" = . ] && continue
[ ".$pe" = .. ] && continue
srcpre="../$srcpre"
done
IFS="$OIFS"
else
if [ $srcisabs = 1 ]; then
srcpre="$prefix"
fi
fi
# determine destination symlink name
if [ ".$dstbase" = . ]; then
if [ ".$srcbase" != . ]; then
dstbase="$srcbase"
else
dstbase=`echo "$prefix$srcdir" | sed -e 's;/*$;;' -e 's;.*/\([^/]*\)$;\1;'`
fi
fi
# special case (usually on "mkln -s /foo /foo/bar", etc)
if [ ".$srcpre$srcdir$srcbase" = . ]; then
srcdir="."
fi
# now finalize source and destination directory paths
srcdir=`echo $srcdir | sed -e 's;\([^/]\)$;\1/;'`
dstdir=`echo $dstdir | sed -e 's;\([^/]\)$;\1/;'`
# run the final link command
if [ ".$opt_t" = .yes ]; then
echo "ln$lnopt $srcpre$srcdir$srcbase $dstpre$dstdir$dstbase"
fi
eval ln$lnopt $srcpre$srcdir$srcbase $dstpre$dstdir$dstbase
done
shtool_exit 0
##
## manual page
##
=pod
=head1 NAME
B<shtool mkln> - B<GNU shtool> enhanced ln(1) replacement
=head1 SYNOPSIS
B<shtool mkln>
[B<-t>|B<--trace>]
[B<-f>|B<--force>]
[B<-s>|B<--symbolic>]
I<src-path> [I<src-path> ...]
I<dst-path>
=head1 DESCRIPTION
This is a ln(1) style command. It is enhanced to provide automatic
calculation and usage of relative links with the shortest possible path,
if possible. Usually if I<src-path> and I<dst-path> are not absolute
paths or at least they share a common prefix except the root directory
(``C</>''). When more than one I<src-path> is specified, all of them are
linked into I<dst-path>.
=head1 OPTIONS
The following command line options are available.
=over 4
=item B<-t>, B<--trace>
Enable the output of the essential shell commands which are executed.
=item B<-f>, B<--force>
Force the creation of the link even if it exists. Default is to fail
with error.
=item B<-s>, B<--symbolic>
Create a symbolic link instead of a hard-link.
=back
=head1 EXAMPLE
# shell script
shtool mkln -s foo/bar baz/quux
=head1 HISTORY
The B<GNU shtool> B<fixperm> command was originally written by Ralf S.
Engelschall E<lt>rse@engelschall.comE<gt> in 1998 for I<ePerl>.
=head1 SEE ALSO
shtool(1), ln(1).
=cut
