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:
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.
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)
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)
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)
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)
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)
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
LEARN ABOUT FREEBSD
tcpdrop
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