# The script take the URL list on the command line
# So, you should call your script like this :
# perl myscript.pl http://site/f1.html http://site/f2.html ...

# Command line arguments are stored in the ARGV list.
# For each URL in ARGV, place this current URL in $_
# $_ the the "default" variable in Perl.
for (@ARGV){

  # Remove the leading "http://" part of $_
  s|http://||;

  # Extract the server name in $1 and the file name in $2
  # from $_ (see "perlre" documentation for this)
  m|([^/]+)(.*)|;

  # Open a tcp socket connection to the server $1 on port 80
  my $s=IO::Socket::INET->new( PeerAddr=>$1, PeerPort=>80, Proto=>'tcp', Type=>SOCK_STREAM );

  # Send a simple HTTP GET request to the server for
  # file $2 or "/" if $2 is not defined.
  print $s "GET ".($2||'/')." HTTP/1.0\nHost: $1 \n\n";

  # Read the first line of the answer (with <$s>) from the 
  # server and print "Link xxx is validated" if the server 
  # answered positively to the request (server answers
  # "HTTP 200 OK" when file is present)
  print "Link $_ is validated\n" if <$s>=~/200 OK/;

  # Close the connection
  close $s;

  # and treat the next URL
}