How To Identify If a Port Is Listening on a Unix Server

Hi all

To see if a port is listening on a Unix Server command is :

           netstat -an | grep port number | grep LISTEN

To see what process is using a port the command is :

           lsof -i tcp:port number

Here a simple perl programm to open a port and check a connection from a client web :


#!/usr/bin/perl -w
        use IO::Socket;
        use Net::hostent;              # for OO version of gethostbyaddr
        $PORT = 8080;

        $server = IO::Socket::INET->new( Proto     => 'tcp',
                                         LocalPort => $PORT,
                                         Listen    => 5,
                                         Reuse     => 1) or die "can't setup server" unless $server;

    printf("\nSERVER Waiting for client connection on port $PORT");

         while ($client = $server->accept()) {

          printf("\nClient Connected\n");

          $client->autoflush(1);
          print $client " You are connected on port $PORT";

          close $client;
        }

Stay tuned

Asn.1 BER Codification Reader in Perl

Today a script in Perl to read files in Asn.1.
Result will be show in BER Codification.


Asn.1 Perl Script


Stay Tuned.

Script PERL : Totals File in a Directory

This is a simple script to show total number of Files in a directory.

Script accepts in input one argument : Directory.

$totfile = 0;

opendir(my $dh, $ARGV[0]) || die;

while(readdir $dh) {

print "$some_dir/$_\n";

$totfile++;

}

closedir $dh;

printf(" Tot Files : $totfile \n");

Stay Connected.

Stat command in Perl (Unix/Linux)

This perl script execute a stat of a file in UNIX/LINUX environment and accept in input file name with absolute path. It shows various file info and atime, mtime and ctime.

#!/usr/bin/perl -w

#

# stat.pl

#

($dev, $ino, $mode, $nlink, $uid, $gid, $rdev, $size,

$atime, $mtime, $ctime, $blksize, $blocks) = stat($ARGV[0]);

print("dev = $dev\n");

print("ino = $ino\n");

print("mode = $mode\n");

print("nlink = $nlink\n");

print("uid = $uid\n");

print("gid = $gid\n");

print("rdev = $rdev\n");

print("size = $size\n");

print("atime = $atime\n");

print("mtime = $mtime\n");

print("ctime = $ctime\n");

print("blksize = $blksize\n");

print("blocks = $blocks\n");

($sec, $min, $hr, $day, $month, $year, $day_Of_Week, $julianDate, $dst) = localtime($ctime);

$year = $year + 1900;

$month = $month + 1;

printf(" ctime $year/$month/$day $hr:$min:$sec\n");

($sec, $min, $hr, $day, $month, $year, $day_Of_Week, $julianDate, $dst) = localtime($mtime);

$year = $year + 1900;

$month = $month + 1;

printf(" mtime $year/$month/$day $hr:$min:$sec\n");

($sec, $min, $hr, $day, $month, $year, $day_Of_Week, $julianDate, $dst) = localtime($atime);

$year = $year + 1900;

$month = $month + 1;

printf(" atime $year/$month/$day $hr:$min:$sec\n");

Stay connected.

Perl : Programming Documentation Site

For some scripts in my work on HP Unix Pa-Risc/Itanium I’m using PERL.
It’s a very good scripting language and I have found this site to help me in script creation:

Site : http://perldoc.perl.org/index-functions.html

I recommend this site, it’s a very good resource and help for Perl programming.

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