CODEWITHSUNDEEP
bashparsing
Shan-x
Shan-x

Reputation: 1176

Parse netstat command to get ports

When i run netstat i have the following outpout :

$ netstat -lnp --inet                                                                 
(Not all processes could be identified, non-owned process info
 will not be shown, you would have to be root to see it all.)
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State        PID/Program name    
tcp        0      0 0.0.0.0:51413           0.0.0.0:*               LISTEN       6155/transmission-g 
tcp        0      0 127.0.0.1:56424         0.0.0.0:*               LISTEN       450/weechat         
netstat: no support for `AF INET (sctp)' on this system.

I want to have the list of the ports using only bash (with python it would be easier). I have this :

$ netstat -lnp --inet | cut -d' ' -f45-50 | sed 's/[^0-9]*//g'                
(Not all processes could be identified, non-owned process info
 will not be shown, you would have to be root to see it all.)
netstat: no support for `AF INET (sctp)' on this system.


6155
450

But i can't get rid of the text. Any help ?

Upvotes: 1

Views: 2714

Answers (3)

Gregory Furmanek
Gregory Furmanek

Reputation: 364

The lines:

(Not all processes could be identified, non-owned process info
will not be shown, you would have to be root to see it all.)

Are sent to stderr instead of stdout so you can get rid of them by sending stderr to /dev/null instead of letting it be printed in the console.

As in:

$ netstat -lnp --inet 2>/dev/null| cut -d' ' -f45-50 | sed 's/[^0-9]*//g'

BTW, piping through egrep "\w" will get rid of the empty lines.

$ netstat -lnp --inet 2>/dev/null| cut -d' ' -f45-50 | sed 's/[^0-9]*//g' | egrep "\w"

Upvotes: 1

Gilles Quénot
Gilles Quénot

Reputation: 185075

More robust with :

netstat -lnp --inet | awk -F'LISTEN *|/' '/^(tcp|udp)/{print $2}' file
6155
450

Upvotes: 4

Kaizhe Huang
Kaizhe Huang

Reputation: 1006

Try:

netstat -lnp --inet | grep -E 'tcp|udp' | cut -d' ' -f45-50 | sed 's/[^0-9]*//g'

Upvotes: 0

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