I'm trying to find (with awk) the IP of a specific ethernet interface using the hostname as a search patter (suffixed by the name of the ethernet interface). I wrote this little script but it outputs nothing and I don't understand why...
#!/bin/bash
name=$(hostname -s)-eth3
IP1=`awk -v var=$name '/var/ {print $1}' /etc/hosts`
echo $IP1
Could you please make few changes as shown following, which may help you.
#!/bin/bash
name=$(hostname -s)-eth3
IP1=$(awk -v var=$name '$0 ~ var{print $1}' "/etc/hosts")
echo "$IP1"
changes like backtick is not encouraged for storing values in bash variables $ should be used and use echo "$var" too.
Inside slashes, awk treats var as a literal string, not a variable.
Thus, replace:
/var/
With:
$0 ~ var
Thus use:
#!/bin/bash
name=$(hostname -s)-eth3
ip1=`awk -v var=$name '$0 ~ var {print $1}' /etc/hosts`
echo "$ip1"
The first awk script below produces no match but the second does:
$ echo host-eth1 | awk -v var='host-eth1' '/var/ {print $1}'
$ echo host-eth1 | awk -v var='host-eth1' '$0 ~ var {print $1}'
host-eth1
