Solved How to get hostname IP address

[fred974]

Hi,

I am writing a script that will be part of a jail flavour...
What I want to do is to add the host IP to /etc/ssh/sshd.conf so it only listen to that IP.

So far I managed to find the IP address using the script bellow:

#!/bin/sh
#
# Test ssh listen address swap

test1=$(ifconfig | grep 'inet')
echo "ListenAddress $test1"

This script return

ListenAddress      inet 10.5.20.15 netmask 0xffffffff

How can I get rid of the 'inet' and the netmask so I am left with only the IP?

Thank you in advance

 

[protocelt]

Try ifconfig <interface> | grep 'inet' | awk -F ' ' '{ print $2 }'

 

[obsigna]

Another option utilizing only one pipe:
ifconfig <interface> | sed -n '/.inet /{s///;s/ .*//;p;}'

 

[protocelt]

Another option utilizing only one pipe:
ifconfig <interface> | sed -n '/.inet /{s///;s/ .*//;p;}'

Yep, this is better. My sed(1)-foo is pretty weak so I chose the cheap route.

 

[wblock@]

I find this easier to read:
ifconfig em0 | grep inet | cut -w -f3

This also works:
ifconfig em0 | awk '/inet/ { print $2 }'

 

[Juha Nurmela]

awk '$1 == "inet" { print $2 }' is handy if you want to weed out inet6

Juha

 

[fred974]

Thank you all

 

[fred974]

Just one more question if I may.

#!/bin/sh
#
# Test ssh listen address swap
hostname_ip=$(ifconfig lo1 | grep inet | cut -w -f3)
#echo "ListenAddress $hostname_ip"


INIFILE="/etc/ssh/sshd_config"
perl -p -i -e '
s/.*#ListenAddress[[:space:]]0.0.0.0.*/ListenAddress $hostname_ip/;
' "$INIFILE"

When I run that script and look at the /etc/ssh/sshd_config I get from

#ListenAddress 0.0.0.0

to

ListenAddress

It is missing the $hostname_ip value.
Can I pass a variable value when running a perl script?
Do I need to do it a different way?

 

[kpa]

Variables are not expanded by sh(1) inside single quotes that you use around the part after -e option for perl(1), use double quotes.

 

[fred974]

On a machine that hasn't got Perl install which of the pkg should iI install for such small job?
is pecl-perl-1.0.1 the right one to go for?

 

[tobik@]

on a machine that hasn't got perl install which of the pkg should i install for such small job?
is pecl-perl-1.0.1 the righ one to go for?

Why not just use: sed -i "" "s/.*#ListenAddress[[:space:]]0.0.0.0.*/ListenAddress $hostname_ip/" /etc/sshd/sshd_config

 

[fred974]

Why not just use: sed "s/.*#ListenAddress[[:space:]]0.0.0.0.*/ListenAddress $hostname_ip/"

Thank you very much

 

[fred974]

tobik the script doesn't work for some reason. I don't get the cursor back and the swap didn't occur.

 

[tobik@]

tobik the script doesn;t work for some reason.. I don't get the cursor back and the swap didn't occur

I have quickly edited the line after I posted it to add -i "" for inline editing, but you were too fast and quoted the old version. Sorry about that. Which one did you use?

 

[fred974]

First one..
Changed it sed -i "" "s/.*#ListenAddress[[:space:]]0.0.0.0.*/ListenAddress $hostname_ip/" /etc/ssh/sshd_config and I'm a very happy chap

Thank you for educating me.. I need to check man to understand how sed work so I know how..