Working with Linux

Save the script, and let's test it.
First, let's get the interface name from the ifconfig command, and then let's go and test the script by
running this command:
iputil --cmd ip --iface wlp3s0
We can see it's printing our private ip on the screen.
Now let's add our last cmd to the script: publicip.
For this we just call the get_public_ip function from our lib utility. Save it and run this:
iputil --cmd publicip
We see that the command worked; our public ip is printed on the screen. Here is the complete script:
#!/bin/bash
CWD=$( cd "$( dirname "${BASH_SOURCE[0]}" )/" && pwd )
cd ${CWD}
source ${CWD}/lib.sh
CMD=$(getarg cmd $@)