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## ## 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 # 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