•Arnošt Havelka
Premium: Bash Script Variables
Master bash variables and arithmetic to build reusable automation scripts that adapt to different environments.
Start Interactive Lesson
Premium: Bash Script Variables
Scripts that hardcode values are fragile. Learn to use variables to make your automation adapt to any situation.
Step 1: Assign and Echo Variables
Command Prompt
myapp
C:\Users\User>echo 'myapp'
Variables store values you'll use multiple times. Store once, reuse forever.
Step 2: Use Variables in Arithmetic
Command Prompt
5
C:\Users\User>echo 5
The $((...)) syntax performs integer math. Perfect for counters, retries, and loops.
Step 3: Build Dynamic Commands with Variables
Command Prompt
Processing backup_001.tar.gz
C:\Users\User>echo 'Processing backup_001.tar.gz'
Double quotes allow $ substitution. Your scripts now adapt without editing the code.
Checklist You Can Reuse
- Create variables with
var='value'(no spaces around=). - Reference variables with
$varor${var}for clarity. - Do math with
$((expression)). - Use double quotes for interpolation:
"prefix_$var_suffix".
Knowledge Check
1 / 2What's the correct syntax to increment a variable?
References
These Microsoft Learn and Windows documentation links provide authoritative details for the commands used in this article.