Dereferencing links

[Kevin D. Clark]

Jim Kuzdrall writes:

>     Is there a command line function to collapse a group of symbolic 
> links, replacing them with the files they reference?

Older editions of the _Programming Perl_ book come with the program
"sl" (for "show links").  Either this does what you want or else it
should be easy to modify this to get what you want.

  $ sl /dev/mouse
   
  /dev/mouse:
  /dev/mouse -> input/mice
       input/mice

Regards,

--kevin
-- 
GnuPG ID: B280F24E                     And the madness of the crowd
alumni.unh.edu!kdc                     Is an epileptic fit
                                       -- Tom Waits



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#!/usr/bin/perl

die "Usage: sl [filenames]\n" unless @ARGV;

# Preliminaries.

$| = 1;
chop($cwd = `pwd`) || die "Can't find current directory: $!\n"
    if @ARGV > 1;
print "\n";

# Do each name.

foreach $name (@ARGV) {
    @indent = ();
    print "$name:\n";
    @path = split(m;/;, $name);

    # Make an absolute path relative to /.

    if (@path && $path[0] eq '') {
	chdir '/';
	shift @path;
	print '/';
	$indent = 1;
    }

    # Now follow the subdirectories and links.

    while (@path) {
	$elem = shift @path;
	$new = readlink($elem);
	if (defined $new) {     # A symbolic link.
	    print "$elem -> $new\n";
	    $new =~ s!^\./!!;

	    # Prepend symbolic link to rest of path.

	    unshift(@path,split(m;/;, $new));

	    # Deal with special cases.

	    if (@path && $path[0] eq '') {

		# Absolute path starts over.

		chdir '/';
		shift @path;
		print '/';
		$indent = 1;
		@indents = ();
		next;
	    }

	    # Back up the tree as necessary.

	    while (@indents && $path[0] eq '..') {
		$indent = pop(@indents);
		chdir '..'
		    || die "\n\nCan't cd to ..: $!\n";
		shift @path;
	    }

	    print "\t" x ($indent / 8), ' ' x ($indent % 8);
	}
	else {                  # An ordinary directory.
	    print $elem;
	    push(@indents,$indent);
	    $indent += length($elem) + 1;
	    if (@path) {
		print '/';
		chdir $elem
		    || die "\n\nCan't cd to $elem: $!\n";
	    }
	}
    }
    print "\n\n";
    $indent = 0;
    chdir $cwd || die "Can't cd back: $!\n" if $cwd ne '';
}