Linux bash script to extract IP address

Question

I want to make big script on my Debian 7.3 ( something like translated and much more new user friendly enviroment ). I have a problem. I want to use only some of the informa

Answer 1

awk '/inet addr:/{gsub(/^.{5}/,"",$2); print $2}' file
192.168.1.103

Answer 2

A slight modification to one of the previous ip route ... solutions, which eliminates the need for a grep:

ip route get 8.8.8.8 | sed -n 's|^.*src \(.*\)$|\1|gp'

Answer 3

If the goal is to find the IP address connected in direction of internet, then this should be a good solution.

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UPDATE!!! With new version of linux you get more information on the line:

ip route get 8.8.8.8
8.8.8.8 via 10.36.15.1 dev ens160 src 10.36.15.150 uid 1002
    cache

so to get IP you need to find the IP after src

ip route get 8.8.8.8 | awk -F"src " 'NR==1{split($2,a," ");print a[1]}'
10.36.15.150

and if you like the interface name

ip route get 8.8.8.8 | awk -F"dev " 'NR==1{split($2,a," ");print a[1]}'
ens192

ip route does not open any connection out, it just shows the route needed to get to 8.8.8.8. 8.8.8.8 is Google's DNS.

If you like to store this into a variable, do:

my_ip=$(ip route get 8.8.8.8 | awk -F"src " 'NR==1{split($2,a," ");print a[1]}')

my_interface=$(ip route get 8.8.8.8 | awk -F"dev " 'NR==1{split($2,a," ");print a[1]}')

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Why other solution may fail:

ifconfig eth0

• If the interface you have has another name (eno1, wifi, venet0 etc)
• If you have more than one interface
• IP connecting direction is not the first in a list of more than one IF

Hostname -I

• May get only the 127.0.1.1
• Does not work on all systems.

Answer 4

ip -4 addr show eth0 | grep -oP "(?<=inet ).*(?=/)"

Answer 5

If you want to get a space separated list of your IPs, you can use the hostname command with the --all-ip-addresses (short -I) flag

hostname -I

as described here: Putting IP Address into bash variable. Is there a better way?

Answer 6

May be not for all cases (especially if you have several NIC's), this will help:

hostname -I | awk '{ print $1 }'