In this guide, I'll show you how to write script in Bash. You can also find several useful examples of bash scripts. So at the end you will get:

  • how to write a script in bash?
  • what is bash
  • bash script examples

What is Bash?

A script in Bash (short for "Bourne-Again shell") is a program written in the Bash programming language. It's mainly used to automate tasks and perform system administration tasks on Linux, macOS, and other Unix-like operating systems.

Here's an example of a simple Bash script that prints: "Hello, World!" to the screen:

echo "Hello, World!"

This script starts with a shebang line - #!/bin/bash. This line specifies the interpreter to use for the script (in this case, /bin/bash).

The second line uses the "echo" command to print the string "Hello, World!" to the terminal.

Write Bash script

Here are the steps to create a Bash script:

  • Create a new file (using a text editor such as nano, vim or emacs)
    • sudo nano
  • Start by shebang line "#!/bin/bash" (always on the top of the file)
  • Write your commands, one per line
  • Save the file and exit the editor
    • CTRL + X + (y) - for nano

Note that the script that you create, needs to be saved with the .sh extension, so that the operating system can recognize it as a shell script..

Run Bash script

First we need to make the file executable by running the command:

chmod +x

Run the script by typing


Bash commands

There are useful commands like:

  • 'if'
  • 'for'
  • 'while'
  • 'case'

to add logic to your script. The script can also take command line arguments, which can be accessed by using the special variables $1, $2, $3, etc, in the script.

Bash script examples

Stop program after X hours

The first example is a script which stops given program in X hours:

date '+%A %W %Y %X'
sleep 2.0h
pkill chrome

Stop program in X min (user input)

Next script shows how to stop the program in X minutes. The X is taken as user input from the terminal:

read -p "How long to delay (60 - 60m)? " answer

echo "Now:" $(date +"%H:%M")
echo "Will end:" $(date -d "+ $answer minute" +'%H:%M')

delay=$(echo "$answer * 60" | bc)
sleep $delay

pkill chrome

Run random song each hour

The next script is starting a program called rhythmbox with a random song from a given folder.

export XDG_RUNTIME_DIR="/run/user/1000"
#ls |sort -R |tail -1 |while read file; do
#    echo "$MUSIC$file"
#	rhythmbox "$MUSIC$file" & sleep 5m
FILE_NAME=$(find /mnt/x/Music/ -type f -iname "*.mp3" | shuf -n1)
rhythmbox  "$FILE_NAME"  & sleep 5m

killall rhythmbox

You need to setup also a CRON job to run this script -

  • Type crontab -e
  • enter the command:
    • 55 9-18 * * * DISPLAY=:0 /home/user/Scripts/cron/

This will run the script from 9 to 18 starting at 55-th minute.

How the script works:

  • export XDG_RUNTIME_DIR="/run/user/1000" - workaround for rhythmbox
  • MUSIC=/mnt/x/Music/ - select the music folder
  • cd $MUSIC - go in the folder
  • find random song in 2 different ways
    • '#' - this is a commented line
  • echo $FILE_NAME - print the name of the selected song
  • start the rhythmbox player and wait 5 minutes
  • finally stop the rhythmbox program