Linux source Command: Load Functions and Variables from Shell Files

The source command is used to read a library file with several functions for the shell in a script file or the command prompt. It searches for library files located in the directories of the PATH variable or from a specific file.

Examples:

$ source funcoes.sh$ source /caminho/ate/diretório/funcoes.sh arg1 arg2

In the example below, we will create a file called minhabiblioteca.sh with the following content:

#!/bin/basheh_o_root(){   [ $(id -u) -eq 0 ] && return $TRUE || return $FALSE}

This file contains a function called "eh_o_root" that returns true if the uid of the logged in user equals zero (root) or false when it returns another value.

Now let's create a script called meuscript.sh that will use minhabiblioteca.sh as a source of functions:

#!/bin/bash# Vamos ler o minhabiblioteca.sh com o comando sourcesource minhabiblioteca.sheh_o_root && echo “Você é o Root.” || echo “Você é um usuário comum.”

Now let's change the permission of meuscript.sh to executable:

$ chmod +x meuscript.sh

When executing meuscript.sh:

$ ./meuscript.shVocê é um usuário comum.

The source command is very useful for reading a library of functions or variables that can be used by several shell scripts.

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