#! /usr/bin/perl -w
use strict;
use File::Copy;

for (@ARGV) {
    my $source = $_;
    next unless -l $source;
    my $target = readlink $source or die "readlink $source: $!";
    my $trap = sub { unlink $source;
		     symlink $target, $source;
		     print "Caught a SIG$_[0]!\n";
		     exit; };
    local ($SIG{HUP}, $SIG{INT}, $SIG{TERM}, $SIG{QUIT}, $SIG{__DIE__}) =
	($trap, $trap, $trap, $trap, $trap);
    unlink $source or die "unlink $source: $!";
    copy $target, $source or die "copy $source to $target: $!";
}