Functions

Definition

Reusable blocks of code within a Bash script. They allow you to group complex commands under a single name, keeping scripts organized and avoiding copy-pasting the same code.

Explain Like I'm New

A mini-script inside your script. You teach the script how to 'CheckDatabase()'. Then, whenever you need to check the database, you just say 'CheckDatabase()' instead of typing out the 20 lines of code again.

Real World Example

A backup script has a function `log_message() { echo "[$(date)] $1" >> backup.log; }`. Throughout the 500-line script, the developer can just type `log_message "Starting backup"` to instantly write neatly formatted timestamps to the log file.

Common Use Cases

•Modular scripting
•Dry (Don't Repeat Yourself) programming

Interview Questions

basic

Do Bash functions require you to define what type of data they return (like integer or string)?

intermediate

How do you pass a variable or argument into a Bash function?

Flash Cards

Question

Define return type?

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Answer

No. Bash is a dynamically untyped language. Functions technically only return numeric exit statuses (0 for success, 1-255 for errors), not data.

Question

Pass arguments?

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Answer

You don't put them in parentheses like other languages. You simply write them after the function name separated by a space (e.g., `my_function "argument1"`). Inside the function, you access it using `$1`.