Functions

As in programming languages, shell functions are blocks of code that can be accessed by their names.

Function definition

Syntax

You define a new function with the following syntax:

name() {
    command1
    command2
    ...
}

Example

greetings() {
  echo hello
}

Storing functions

You can define a new function directly in the terminal. Such a function would however only be available during your current session. Since functions contain code that is intended to be run repeatedly, it makes sense to store function definitions in a file. Before functions become available, the file needs to be sourced (e.g. source file.sh).

A convenient file is ~/.bashrc. The file is automatically sourced every time you start a shell so your functions will always be defined and ready for use.

Here is a video of a previous version of this workshop.