Sponsored Content
Full Discussion: Perl- check the port used
Top Forums Shell Programming and Scripting Perl- check the port used Post 302523555 by pludi on Thursday 19th of May 2011 05:41:20 AM
Old 05-19-2011
Reading from a filehandle, such as STDIN, will always read all characters up to and including the new line character(s), and save them to the variable given on the left side. That means when your user inputs (for example) "22" and then hit return, $port will actually contain "22\n" (on Unix) or "22\r\n" on Windows or "22\r" on MacOS. chomp will remove any non-printable characters at the end of the line for you. Try this small script:
Code:
#!/usr/bin/perl

use strict;
use warnings;

print "Enter something: ";
my $input1 = <STDIN>;
print "You wrote >>$input1<<\n";

print "Enter something again: ";
my $input2 = <STDIN>;
chomp $input2;
print "You wrote >>$input2<<\n";

See the difference?

Now when you try to match the contents of $port on line 7, Perl is trying to match (with the example 22 again) ":22<newline>" exactly. Since the port number isn't at the end of netstats output, it will never match.

As for point 3, take a look at the (aptly named) grep function.
This User Gave Thanks to pludi For This Post:
 

10 More Discussions You Might Find Interesting

1. IP Networking

how can i check if port is busy or if someone is using it ?

Hello i have application that using ports , how can i check if the port im using is not captured by any applications? (1 Reply)
Discussion started by: umen
1 Replies

2. IP Networking

How can I check what port addresses used the application

Hello Mentors! I am a new here in the furom, i hope somebody can understand my problem. Basically we have an application here called unigraphics and being installed per station and the setup is look like this. 1. installed unigraphics UGNX3 version on every station 2. some are installed in... (1 Reply)
Discussion started by: eykyn17
1 Replies

3. Solaris

How to check that a device is attached on a port

Q1: can anyone tell me how cfgadm keeps track of the device even if the device is disconnected , when we disconnect a device using cfgadm cfgadm -ys disconnect <ap_id> then the device disappears from the lshal o/p. HAL uses libdevinfo for the device list. if the device is not there in the... (2 Replies)
Discussion started by: narendra.pant
2 Replies

4. UNIX for Dummies Questions & Answers

How do you check whether a port currently being used?

Hi, Please help me out, how to check whether a port currently being used or not. is there any command which give the result? Thanks Rajesh (6 Replies)
Discussion started by: rajesh08
6 Replies

5. Shell Programming and Scripting

How to check if a Port is accepting connections.

Hi, I need to create a script which checks the availability of a particular service on a particular Port on HP-Unix. Is there any command in unix wherein we can check if any port is accepting the connections now. Thanks, Vihang. (5 Replies)
Discussion started by: vikings.svnit
5 Replies

6. Shell Programming and Scripting

Perl code to check date and check files in particular dir

Hi Experts, I am checking how to get day in Perl. If it is “Monday” I need to process…below is the pseudo code. Can you please prove the code for below condition. if (today=="Monday" ) { while (current_time LESS THAN 9:01 AM) ... (1 Reply)
Discussion started by: ajaypatil_am
1 Replies

7. Shell Programming and Scripting

How to check UDP port example = 31011?

We have open port UDP port 31011, how to verify if port were working or traffic were receive. (2 Replies)
Discussion started by: avtalan
2 Replies

8. Red Hat

How to check port used for SSL?

I have RHEL 5.8 in our production environment. We are using SSL, my query is how to find the port used for SSL. In /etc/services, it shows 443 but when I give netstat -tulpn | grep 443 Or netstat -tulp | grep https I do not get any output. I hope, my question is clear of how to find... (4 Replies)
Discussion started by: RHCE
4 Replies

9. Shell Programming and Scripting

How to check empty port using netstat?

Hi, How to check empty port using netstat please help Thanks Ashfaque (3 Replies)
Discussion started by: ashfaque
3 Replies

10. Shell Programming and Scripting

How to check the IP:PORT firewall uses?

I have my firewall process running # ps -ef | grep firewall root 21169 1 0 08:50 ? 00:00:00 /usr/bin/python -Es /usr/sbin/firewalld --nofork --nopid I wish to know what ip : port number it is using. Can you please tell me how can i find out ? I tried the below command... (4 Replies)
Discussion started by: mohtashims
4 Replies
TCPDROP(8)						    BSD System Manager's Manual 						TCPDROP(8)

NAME
tcpdrop -- drop TCP connections SYNOPSIS
tcpdrop local-address local-port foreign-address foreign-port tcpdrop [-l] -a DESCRIPTION
The tcpdrop command may be used to drop TCP connections from the command line. If -a is specified then tcpdrop will attempt to drop all active connections. The -l flag may be given to list the tcpdrop invocation to drop all active connections one at a time. If -a is not specified then only the connection between the given local address local-address, port local-port, and the foreign address foreign-address, port foreign-port, will be dropped. Addresses and ports may be specified by name or numeric value. Both IPv4 and IPv6 address formats are supported. The addresses and ports may be separated by periods or colons instead of spaces. EXIT STATUS
The tcpdrop utility exits 0 on success, and >0 if an error occurs. EXAMPLES
If a connection to httpd(8) is causing congestion on a network link, one can drop the TCP session in charge: # sockstat -c | grep httpd www httpd 16525 3 tcp4 192.168.5.41:80 192.168.5.1:26747 The following command will drop the connection: # tcpdrop 192.168.5.41 80 192.168.5.1 26747 The following command will drop all connections but those to or from port 22, the port used by sshd(8): # tcpdrop -l -a | grep -vw 22 | sh SEE ALSO
netstat(1), sockstat(1) AUTHORS
Markus Friedl <markus@openbsd.org> Juli Mallett <jmallett@FreeBSD.org> BSD
January 30, 2013 BSD
All times are GMT -4. The time now is 10:58 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy