Functions

As in programming language, 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 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.