Export commands are essential in Unix-like operating systems for setting environment variables, which are critical for the configuration and behavior of software applications. In the Apple environment, specifically macOS, the Terminal application allows users to utilize export commands to manage these environment variables effectively. This is important for developers and system administrators who need to configure their development environments, automate tasks, and ensure that applications run with the correct settings.

Examples:

1. Setting an Environment Variable:

   To set an environment variable in macOS Terminal, you can use the export command. For example, to set the JAVA_HOME variable to point to your Java installation directory, you would use:

   export JAVA_HOME=/Library/Java/JavaVirtualMachines/jdk-11.0.1.jdk/Contents/Home

   This command sets the JAVA_HOME variable for the current session. To verify that it has been set correctly, you can use the echo command:

   echo $JAVA_HOME

2. Making Environment Variables Persistent:

   If you want to make an environment variable persistent across terminal sessions, you need to add the export command to your shell's configuration file. For example, if you are using the Bash shell, you would add the export command to your .bash_profile or .bashrc file:

   echo 'export JAVA_HOME=/Library/Java/JavaVirtualMachines/jdk-11.0.1.jdk/Contents/Home' >> ~/.bash_profile

   For the Zsh shell, which is the default shell in macOS Catalina and later, you would add it to your .zshrc file:

   echo 'export JAVA_HOME=/Library/Java/JavaVirtualMachines/jdk-11.0.1.jdk/Contents/Home' >> ~/.zshrc

   After adding the export command to the appropriate file, you need to source the file to apply the changes:

   source ~/.bash_profile  # For Bash
   source ~/.zshrc         # For Zsh

3. Exporting Multiple Variables:

   You can export multiple environment variables in a single command by separating them with a space. For example:

   export PATH=$PATH:/usr/local/bin JAVA_HOME=/Library/Java/JavaVirtualMachines/jdk-11.0.1.jdk/Contents/Home

   This command adds /usr/local/bin to the existing PATH variable and sets the JAVA_HOME variable.

4. Unsetting Environment Variables:

   To remove an environment variable, you can use the unset command. For example, to unset the JAVA_HOME variable:

   unset JAVA_HOME