[English] Debian Almquist Shell (dash) export Usage equivalent in English: Set environment variables

Overview

The export command in the Debian Almquist Shell (dash) is used to set environment variables that can be accessed by child processes. When a variable is exported, it becomes part of the environment for any subsequently executed commands.

Usage

The basic syntax of the export command is as follows:

export [options] [arguments]

Common Options

• -n: Unsets the export attribute for the specified variable, making it no longer available to child processes.
• -p: Displays all exported variables and their values.

Common Examples

Example 1: Exporting a Variable

To export a variable named MY_VAR with the value Hello World, you can use:

MY_VAR="Hello World"
export MY_VAR

Example 2: Exporting Multiple Variables

You can export multiple variables in a single command:

export VAR1="Value1" VAR2="Value2"

Example 3: Unsetting an Exported Variable

To unset the export attribute of a variable, use the -n option:

export -n MY_VAR

Example 4: Displaying Exported Variables

To display all currently exported variables, use the -p option:

export -p

Tips

• Always ensure that the variable names you choose do not conflict with existing environment variables to avoid unexpected behavior.
• Use export before running scripts that rely on specific environment variables to ensure they are available.
• Remember that changes made to exported variables in a shell session will not persist after the session ends unless they are added to a startup file like .bashrc or .profile.