How to find the IP address of the local Linux workstation

I am creating a shell script that should do some local settings and echo the IP of the machine in a text file. The reason I need to do this is to get the IP in a PHP script and use it from there as root for a site.

I can get the IP using ifconfig but I need to strip the useless information. I’d like to do this in the shell script not in the PHP file.

The OS is CentOS 5.5, I need the IP of eth0.

Well ip -4 -o addr show dev eth0 will get you a reasonably nice one line output showing the address but it will need some parsing to extract the address. Something like this should work:

ip -4 -o addr show dev eth0 | awk '{ gsub(//[0-9]+$/, "", $4); print $4 }'

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