Running functions in the background

We have already seen in previous chapters that to run any command in the background, we have to terminate the command using &:

$ command &

Similarly, we can make the function run in the background by appending & after the function call. This will make the function run in the background so that the terminal will be free:

#!/bin/bash
dobackup()
{
    echo "Started backup"
    tar -zcvf /dev/st0 /home >/dev/null 2>&1
    echo "Completed backup"
}
dobackup &
echo -n "Task...done."
echo

Test the script as follows:

$ chmod +x function_17.sh
$ ./function_17.sh

Output:

Task...done.
Started backup
Completed backup

Command source and period (.)

Normally, whenever we enter a command, the new process gets created. If we want to make functions from the script to be made available in the current shell, then we need a technique that will run the script in the current shell instead of creating a new shell environment. The solution to this problem...