For finding out which ports of the machine are being opening by which services, I used:
netstat -tulpn
I checked the man
page for netstat
command, but I found nothing about this option. What's the meaning of the -tulpn
option?
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Sign up to join this communityFor finding out which ports of the machine are being opening by which services, I used:
netstat -tulpn
I checked the man
page for netstat
command, but I found nothing about this option. What's the meaning of the -tulpn
option?
As answered in https://serverfault.com/questions/387935/whats-the-difference-betwen-the-single-dash-and-double-dash-flags-on-shell-comm, in a Linux command line;
A single hyphen can be followed by multiple single-character flags.
A double hyphen prefixes a single multi-character option.
If you look at netstat man page, you will see that (Note that, netstat -tulpn
is equivalent to netstat -t -u -l -p -n
):
--tcp|-t
--udp|-u
-l, --listening
Show only listening sockets. (These are omitted by default.)
-p, --program
Show the PID and name of the program to which each socket belongs.
--numeric, -n
Show numerical addresses instead of trying to determine symbolic host, port or user names.
So, your command is equivalent to the following long form also:
netstat --tcp --udp --listening --program --numeric
In addition to man netstat
you can type info netstat
to get a shorter summary and longer explanation:
NETSTAT(8) Linux Programmer's Manual NETSTAT(8)
NAME
netstat - Print network connections, routing tables, interface statistics, mas‐
querade connections, and multicast memberships
SYNOPSIS
netstat [address_family_options] [--tcp|-t] [--udp|-u] [--raw|-w] [--listening|-l]
[--all|-a] [--numeric|-n] [--numeric-hosts] [--numeric-ports] [--numeric-users]
[--symbolic|-N] [--extend|-e[--extend|-e]] [--timers|-o] [--program|-p] [--ver‐
bose|-v] [--continuous|-c]
For -t -u -l -p -n
above you see --tcp
, --udp
, --listen
, --program
and --numeric
without having to scroll.
Scrolling down you can see verbose explanations.
Looks like you were looking for the man page for netstat(8).
Linux.die.net has man pages for seemingly all Linux tools. See below the man page for netstat(8) which should answer your question.
man
page for netstat
command. However, thank you for your response.
Mar 16, 2020 at 10:41
man netstat
?--tcp
or--udp
), and the short form starts with a single dash (e.g,-t
or-u
.) And as you have just discovered, some commands allow the short form options to be combined. There are plenty of exceptions, though! Off the top of my head I can think oftar
which accepts options with or without the dash (e.g.,tar xvzf foo.tgz
is the same astar -xvzf foo.tgz
), so always checkinfo
orman
pages if in doubt.