Variables In Scripts

Variables make your scripts flexible and reusable. Instead of hardcoding values, you can store them in variables and reference them throughout your script.

To create a variable inside a script, use the same syntax you learned for the terminal: no spaces around the equals sign. To use the variable's value, prefix its name with a dollar sign:

#!/bin/bash
greeting="Hello"
name="World"
echo "$greeting, $name!"

This script outputs Hello, World!. The variables greeting and name store text that gets substituted when the script runs.

Variables become especially useful when you need to use the same value multiple times. If you reference a file path in several places, storing it in a variable means you only need to change it once:

#!/bin/bash
backup_dir="/home/user/backups"
echo "Creating backup in $backup_dir"
mkdir -p "$backup_dir"

Notice the quotes around "$backup_dir". Wrapping variables in double quotes is good practice because it handles paths or values that contain spaces correctly. Without quotes, a path like /my documents would break your command.

Variables in scripts work just like in the terminal, but they exist only while the script runs. Once the script finishes, those variables disappear.