#!/usr/local/bin/perl -w
######################################################################
# excat -- 2004, Mike Schilli <mschilli@yahoo-inc.com>
######################################################################
# cat, but synchronizing access via file.lock
######################################################################
use strict;

my  $VERSION    = "0.01";
my  $CVSVERSION = '$Revision: 1.2 $';

use Fcntl qw/:flock/;
use Getopt::Std;

my $lockfile = ".lock";
getopts("l:", \my %opts);
$lockfile = $opts{l} if exists $opts{l};

open(WFILE, ">>$lockfile") ||
    die "Error opening $lockfile ($!)";

flock(WFILE, LOCK_EX);    # start of critical region

while(<>) {
    print;
}

close(WFILE);
unlink $lockfile; # might fail

__END__

=head1 NAME

    excat - cat command with file locking

=head1 DOWNLOAD

_SRC_HERE_

=head1 SYNOPSIS

    cat source | excat -l file.lock >>dest

=head1 OPTIONS

=over 8

=item B<-l>

Specify the name of the lock file. Defaults to '.lock'.

=back

=head1 DESCRIPTION

C<excat> acts like C<cat>, but creates a lockfile and ensures
exclusive access before opening the output stream.

=head1 EXAMPLES

  $ excat -l file.lock sourcefile >>destfile
  $ cat sourcefile | excat -l file.lock >>destfile

=head1 LEGALESE

Copyright 2004 by Mike Schilli, all rights reserved.
This program is free software, you can redistribute it and/or
modify it under the same terms as Perl itself.

=head1 AUTHOR

2004, Mike Schilli <m@perlmeister.com>