The secret of environment variable operation: Linux command line export skills

Allow me to briefly explain to you the export command commonly found in the Linux command line. It is essential for adjusting environment variables and helps us to conveniently utilize environment variables in existing sessions or sub-processes. Below are my detailed answers to your questions.

1. What are environment variables?

Environment variables play an important role in the operating system. Linux checks port occupancy, stores various key information, and plays a decisive role in the normal operation of the system. For example, the PATH variable is used to specify the folder path that can be retrieved when executing the command.

2. How to view the current environment variables?

Please pay attention to linux when sending emails. Just add the dollar sign ($) after the echo command, and we can easily query various variables in the current environment! For example, just enter echo $PATH to quickly learn what the current PATH variable is set to.

3. How to set an environment variable?

You can easily define an environment variable by entering a simple export command! The correct format is: export variable name = value. For example, you can try to execute the following command: export MYVAR=hello, which will successfully create an environment variable named MYVAR and assign it the value "hello".

4. How to delete an environment variable?

To clear the specified environment variable, you can try using the "unset" command. The specific syntax is "unset variable name". For example, if you want to delete an environment variable named 'MYVAR', you can easily do so by typing "unset MYVAR".

5. How to export an environment variable to a child process?

When the parent process sets an environment variable, it is expected that its child processes can also enjoy this convenience. At this time, we can use the export command to solve this problem well. For example, by executing the export MYVAR command, we can successfully pass the MYVAR environment variable to the child process.

6. How to view all current environment variables?

Congratulations on discovering the env command, it can show you all currently available environment variables and their corresponding values! With just one click, you can see these variables.

7. How to save an environment variable permanently?

Dear users, if you want the environment variable to still take effect after restarting, it is recommended that you add it to the corresponding configuration file. For most Linux operating systems, such configuration files are usually stored in the ".bashrc" or ".bash_profile" file in the personal home directory. You only need to add "export variable name=value" at the bottom of the file to achieve this function.

8. How to make the newly added environment variables take effect immediately?

If you want the new environment specified by the export command to be executed immediately use the linux export command , just follow it with the "source" command. For example, simply enter "source ~/.bashrc" to make the environment variables you just set work immediately!

Here, we hope that through relevant inquiries and answers, you will have a deeper understanding of the flexible application of the Linux export command. Whether you use the linux export command to set, remove or display environment variables, the export command can provide convenience. We hope this article will bring you real benefits. Thank you very much for taking the time to read!

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