Obtain Remote linux Server IP address' using bash script via ssh

Question

I need to Obtain my remote Linux Server eth1 IP address using bash script through the ssh and i have following command: /sbin/ifconfig eth1 | grep 'inet addr:'| grep -v '127.0.0.1' | cut -d: -f2 | awk '{ print $1}'

but when i run :

spawn ssh -t $user@$remote_host "/sbin/ifconfig eth1 | grep 'inet addr:'| grep -v '127.0.0.1' | cut -d: -f2 | awk '{ print $2}' ; echo $ip " it says can't read "1": no such variable while executing "spawn ssh -t $user@$remote_host "ip=/sbin/ifconfig eth1 | grep 'inet addr:'| grep -v '127.0.0.1' | cut -d: -f2 | awk '{ print $1}' ; echo $ip "" (file "./ssh2.sh" line 11)

So could please help me with this issue. Thanks

Answer 1

Why not use ip instead of the deprecated ifconfig, and skip all the extra greps and cuts since awk can do that.

So a command like ip addr show dev eth0 | awk '/^ +inet / {split($2,a,"/"); print a[1]}'

In any case, most of your problem in your example commands have to do with the type of quotes you choose, and how bash evaluates them.

If you do something like cfrancy@ws:~$ ssh root@srv01 echo "Hello $USER" then the output you will see is Hello cfrancy, and not Hello root like you might expect. Because you have used double quotes " around your command for the remote system, all the variables are evaluated before the command is sent. The command cfrancy@ws:~$ ssh root@srv01 echo 'Hello $USER' will return Hello root since the $USER is evaluated on the remote site. Of course you also need to switch around or escape your other quotes inside your compound command so things work out properly.

Anyway, keeping the quoting behavior in mind the command would probably do what you want. though I think my solution that uses only ip, and awk is a better choice since I am only useing 2 programs instead of 4.

ssh -t $user@$remote_host '/sbin/ifconfig eth0 | grep "inet addr:"| grep -v "127.0.0.1" | cut -d: -f2 | awk "{ print $1}"'