Linux Shell Scripting Cheat Sheet/Define shell function

Create a reusable shell function.

Section: Conditionals Loops and Functions

Define shell function

bash
bash
greet() { echo "hello $1"; }
Explanation

Functions help keep scripts readable and avoid repetition.

Learn the surrounding workflow

Compare similar commands or jump into common fixes when this command is part of a bigger troubleshooting path.

Related commands

Same sheet · prioritizing Conditionals Loops and Functions
Check whether file exists
Use a shell test in an if statement.
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Check whether directory exists
Test for directory presence.
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Loop over items
Iterate through words or filenames.
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Read file line by line
Process lines safely using while-read.
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Branch with case
Match input against multiple patterns.
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Enable strict shell behavior
Fail script on errors and unset vars.
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