Running loops in the background

In certain situations, the script with loops may take lot of time to complete. In such situations, we may decide to run the script containing loops in the background so that we can continue other activities in the same terminals. The advantage of this will be that the terminal will be free for giving the next commands.

The following for_15.sh script is the technique to run a script with loops in the background:

#!/bin/bash
for animal in Tiger Lion Cat Dog
do
     echo $animal
    sleep 1
done &

Let's test the program:

$ chmod +x for_15.sh
$ ./for_15.sh

The following will be the output after executing the preceding commands:

Tiger
Lion
Cat
Dog

In the preceding script, the for loop will process animals Tiger, Lion, Cat, and Dog sequentially. The variable animal will be assigned the animal names one after another. In the for loop, the commands to be executed are enclosed between do and done. The ampersand after the done keyword will make the for loop run in...