If you’re new to Bash scripting, loops are one of the most powerful tools you can learn. They help automate repetitive tasks, making your work as a DevOps engineer much more efficient.
In this guide, we’ll cover the basics of for and while loops in Bash, along with practical examples you might use in real-world DevOps scenarios.
What Are Loops?
Loops allow you to repeat a block of code multiple times. The two most common types in Bash are:
- for loops – Run a command for each item in a list.
- while loops – Run a command as long as a condition is true.
The for Loop
A for loop allows you to process a list and run some commands with that list item as a variable. The example below loops through all of the files in /var/log, tells the user what file it’s processing an the puts them all in a file called log.errors.
for file in /var/log/*.log; do
echo "Processing: $file"
grep "error" "$file" >> "log.errors"
doneCode language: Bash (bash)