What you will learn
- Use conditionals and tests
- Iterate with loops
- Work with arrays
New to this? Start here
The basics, in plain English
To do anything useful, a script needs to remember values and make decisions. Variables store values, loops repeat actions, and conditionals choose between paths. These three ideas exist in every programming language.
- Variable
- A named box that holds a value, like name="Alice", so you can reuse it later.
- Loop
- A way to repeat the same steps many times, such as once for every file.
- Conditional (if)
- A check that runs one block of code only when something is true.
- Comparison
- Testing whether two things are equal, bigger, smaller, or a file exists.
- Array
- A variable that holds a list of values instead of just one.
01
Control flow
if/elif/else with [[ ]] tests, for and while loops, and case statements cover almost everything you need in ops scripts.
Try it yourself
bash
$for f in *.log; do↳Loop over every .log file in the folder.$ [[ -s "$f" ]] && gzip "$f"↳If the file is non-empty, compress it.$done↳End of the loop.↳ lines explain what each command does — only the commands get copied
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