Why process control manages execution in Bash Scripting

Introduction

Process control helps you decide when and how commands run in your script. It makes sure tasks happen in the right order and at the right time.

You want to run one command only if another command succeeds.

You need to run multiple commands at the same time to save time.

You want to stop a script if a command fails to avoid errors.

You want to wait for a background task to finish before continuing.

You want to run commands one after another in a specific order.

Syntax

Bash Scripting

command1 && command2
command1 || command2
command1 &
wait
if command; then ... fi

Use && to run the next command only if the first one succeeds.

Use & to run a command in the background so the script keeps running.

Examples

Create a folder and only change into it if creation worked.

Bash Scripting

mkdir new_folder && cd new_folder

Try to ping a site; if it fails, print a message.

Bash Scripting

ping -c 1 example.com || echo "Ping failed"

Run sleep in the background and immediately print a message.

Bash Scripting

sleep 10 &
echo "Waiting in background"

Run sleep in background, wait for it to finish, then print.

Bash Scripting

sleep 5 &
wait
echo "Done waiting"

Sample Program

This script creates a folder and tells you if it worked. Then it runs a 3-second sleep in the background, prints a message, waits for sleep to finish, and prints again.

Bash Scripting

#!/bin/bash

mkdir test_dir && echo "Folder created" || echo "Failed to create folder"

sleep 3 &
echo "Sleeping in background"
wait
echo "Background task finished"

Important Notes

Using && and || helps control what happens next based on success or failure.

Running commands in the background with & lets your script do other things at the same time.

The wait command pauses the script until all background tasks finish.

Summary

Process control manages when and how commands run in a script.

Use && and || to run commands conditionally based on success or failure.

Use & and wait to run tasks in the background and wait for them.