Introduction to Linux Environment Variables
In the large and complex world of Linux, the environment plays an important role in how the operating system behaves in the context of embedded applications. These changes are important for users and administrators because they provide a way to influence shell sessions and the working environment of applications. Understanding and managing these changes can make your Linux experience much easier.
Prerequisites for environmental variables management
Before proceeding with the commands needed to monitor and control the environment, make sure you have:
- Accessing the Linux terminal.
- Appropriate permissions to view or modify the desired variables.
- Basic knowledge of shell commands and Linux terminal operations.
Comprehensive Guide on How to Display Linux Environment Variables
Learn multiple ways of viewing and managing your Linux environment variables effortlessly:
- Using the
printenvCommand:- Simply type
printenvto display all environment variables. - To focus on one variable, you can use
printenv [VARIABLE_NAME]. - For a paginated view, append
| lessor| moreto the command.
- Simply type
- The
envCommand:envdisplays all exported environment variables. It’s particularly useful for seeing the environment settings that will be passed to any program run from the shell.- To filter and view specific variables, you can pipe the output to
grep, like so:env | grep HOME.
- Leveraging the
setCommand:- The
setcommand is useful for a comprehensive view, listing both environment variables and shell functions, which can be particularly insightful for scripting and debugging purposes.
- The
Frequently Used Environmental Variables in Linux
Knowing the frequently used environmental variables will help you operate and set up your linux system correctly. Below is a rapid reference guide:
| Variable | Description | Example Command |
PATH | Specifies the directories in which executable programs are located. | echo $PATH |
HOME | Indicates the current user’s home directory. | echo $HOME |
USER | Shows the username of the current user. | echo $USER |
SHELL | Indicates the path of the current user’s shell, like Bash. | echo $SHELL |
LANG | Sets the current language and locale settings. | echo $LANG |
HISTSIZE | Sets the limit for the number of stored commands in history. | echo $HISTSIZE |
LOGNAME | Records the name of the current user. | echo $LOGNAME |
TERM | Specifies the type of terminal to emulate when running the shell. | echo $TERM |
EDITOR | Defines the default text editor. | echo $EDITOR |
PS1 | Return user prompt settings. | echo $PS1 |
How to Manage Environment Variables
To modify or set new environment variables, use the following syntax:
- To set a variable:
export VARIABLE_NAME='value'- eg:
export COMPANY=Quadrect
- eg:
- To remove a variable:
unset VARIABLE_NAME- eg:
unset COMPANY
- eg:
Saving and Sharing Environment Settings
For situations where you need to save or share environment settings:
- Save your environment configuration to a file using
printenv > saved_quadrect_env.txt.
- Extract the configuration from the file using. (make sure the file format and contents are correct before sourcing).
source saved_quadrect_env.txt
Wrap-up
It is very important to know how to open and control environment variables because it’s a key aspect of mastering Linux. This knowledge will enable you as a developer, system administrator or just a fan of Linux to configure your machine in a way that suits your requirements better. Ensure you check quadrect.com regularly for additional informative tutorials and hints on maximizing the potential of your Linux system.
