•Arnošt Havelka
Premium: Bash Script Automation
Combine loops and conditionals to build scripts that run tasks automatically and respond to system state.
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Premium: Bash Script Automation
Loops and conditionals are the backbone of automation. Master them and you'll write scripts that handle complex workflows effortlessly.
Step 1: Loop Over a List
Command Prompt
web
app
db
C:\Users\User>echo web
echo app
echo db
The for loop iterates over a list. One line replaces three.
Step 2: Loop Over Files
Command Prompt
app.log
system.log
C:\Users\User>ls *.log
Process files in batch. No need to run commands individually.
Step 3: Conditional Execution
Command Prompt
Proceed
C:\Users\User>retries=4
echo 'Proceed'
Conditionals let your script make decisions. Check file existence, compare numbers, test conditions.
Checklist You Can Reuse
- Loop with
for var in list; do commands; done. - Use
for file in *.extto process files in batch. - Test with
if [ condition ]; then commands; fi. - Comparisons:
-eq(equal),-gt(greater),-lt(less),-f(file exists).
Knowledge Check
1 / 2Which loop structure processes every .sh file in the current directory?
References
These Microsoft Learn and Windows documentation links provide authoritative details for the commands used in this article.