Hayl_ has asked for the wisdom of the Perl Monks concerning the following question:

I have the following code - which strings together nmap, fuser, and ps and gives me pretty output. The problem I have is that some subscripts of @pid array contain a list instead of a scalar so when it prints I get strangely formatted output. 
use strict;

# Variables

my @nmap;
my @port;
my @protocol;
my @pid;
my @app;
my $junk;
my $i;
print "\nScanning for open ports... ";
chomp(@nmap = `nmap localhost`);
for (1..5) {
    shift(@nmap);
}
for (1..2) {
    pop(@nmap);
}
$i = 0;
foreach (@nmap) {
        if (! @nmap[$i] =~ /^\s*$/) {
                (@port[$i], @protocol[$i]) = split /\//, $_;
                @protocol[$i] = split / /, @protocol[$i];
                @pid[$i] = `fuser -n @protocol[$i] @port[$i]`;
                chomp(($junk, @pid[$i]) = split /:\s+/,@pid[$i]);
                @app[$i] = `/bin/ps --no-headers -o %c @pid[$i]`;
                $i++;
        }
}
print "done.\n\n";
print "The following ports are open on your system\n\n";
printf "%8s%12s%12s%15s\n","Port", "Protocol", "PID", "App";
print "-----------------------------------------------\n";

$i = 0;
foreach (@nmap) {
    printf "%8s%12s%12s%16s\n", @port[$i], @protocol[$i], @pid[$i][1],
+ @app[$i];
    $i++;
}

[download]
good looking output where there is only one PID per port: 
Scanning for open ports... done.

The following ports are open on your system

    Port    Protocol         PID            App
-----------------------------------------------
      22         tcp       21232           sshd

     515         tcp       21943            lpd

    6000         tcp        1738              X

[download]
bad looking output with multiple PIDs per port: 
Scanning for open ports... done.

The following ports are open on your system

    Port    Protocol         PID            App
-----------------------------------------------
      25         tcp         198           exim

      53         tcp         226          named

     139         tcp242  3995  3997  4007  4009  4011           smbd

     143         tcp   269  1006         xinetd

[download]
I think I know what I want to do but I don't know how to do it. I want to print the first item in the @pid$i list and then have a foreach loop to print the rest after the first line.

Replies are listed 'Best First'.
Re: @pid = a list - need a way to print
by CombatSquirrel (Hermit) on Aug 22, 2003 at 13:46 UTC
    Substitute the lines 
    foreach (@nmap) {
   printf "%8s%12s%12s%16s\n", @port[$i], @protocol[$i], @pid[$i][1], 
+@app[$i];
   $i++;
}

    [download]
    by 
    foreach (@nmap) {
   my @pids = @pid[$i][1];
   printf "%8s%12s%12s%16s\n", @port[$i], @protocol[$i], shift(@pids),
+ @app[$i];
   for (@pids) {
      printf " " x 20 . %12s" . " " x 16 . "\n", shift(@pids);
   }
   ++$i;
}

    [download]
    I'm not using Unix, so I can't test it, but it should work.
    Cheers, CombatSquirrel.
[reply]
[d/l]
[select]
      thanks! you pointed me in the right direction. i ended up with this code: 
      #!/usr/bin/perl
#
# App Name:    pscan.pl
# Written By:     DKD (dale_d at telusplanet dot net)
# 
# uses nmap, fuser, and ps to display the port number,
# protocol, pid, and executable name for each open
# port in a readable format.
#
# Requires:    nmap, fuser, ps 
#
# Usage:     pscan.pl
#        No switches

use strict;

# Variables

my @temp;
my @nmap;
my @port;
my @protocol;
my @pid;
my @pids;
my @app;
my $whoami;
my $junk;
my $i;

# Check to see if you are root, and then display some text.

$whoami = `whoami`;
chomp($whoami);
die "You must run pscan as root!\n" unless ( $whoami eq "root");
print "\nScanning for open ports.";

# Grab input from nmap and discard any output lines that we
# don't want (any that don't start with numeric characters).

chomp(@temp = `nmap localhost`);
foreach (@temp) {
    push(@nmap, $_) if $_ =~ /^\d+/;
}

# Iterate through the output from nmap and extract the port
# and protocol, then use the port and protocol to get the
# PID from the fuser command, then use ps to get the name of
# the executable from the pid.

$i = 0;
foreach (@nmap) {
    (@port[$i], @protocol[$i]) = split /\//, $_;
        @protocol[$i] = split / /, @protocol[$i];
        @pid[$i] = `fuser -n @protocol[$i] @port[$i]`;
        chomp(($junk, @pid[$i]) = split /:\s+/,@pid[$i]);
    chomp(@app[$i] = `/bin/ps --no-headers -o %c @pid[$i]`);
        $i++;
    print ".";
}

# Display the data in a readable format

print "done." . "\n" x 2;
# print the header
print "  The following ports are open on your system:\n\n";
printf "%8s%12s%12s%16s\n","Port", "Protocol", "PIDs", "Process";
print "-" x 48 . "\n";
$i = 0;
foreach (@nmap) { # print the port, protocol, first pid, and app(proc)
    chomp(@pids = split / +/, @pid[$i]);
    printf "%8s%12s%12s%16s\n", @port[$i], @protocol[$i], shift(@pids)
+, @app[$i];
    foreach (@pids) { # print any pids if there are more than one.
        printf "%32s\n", $_;
    }
    print " -" x 24 ."\n"; # dashed line separating each port
   ++$i;
}

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