In-depth understanding of common Linux environment variables

Detailed explanation of commonly used environment variables in Linux

In the Linux system, environment variables are values ​​that can affect the running of the program. Environment variables store some key information, such as path, user name, operating system type, etc. This article will introduce some commonly used Linux environment variables and provide specific code examples.

1. PATH
   PATH is a very important environment variable, which defines the directories in which the Shell searches for executable files. The directories listed in PATH will be searched in order. When you enter a command, the system will look for the corresponding executable file in these directories.

Sample code:

echo $PATH

Output example:

/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin

In the above example, the PATH environment variable contains multiple directories, and the system will search for them in this order. executable file.

2. HOME
   HOME is the current user's home directory, which is generally used to store the user's personal files and settings. When a user logs in to the system, he or she will automatically switch to the HOME directory.

Sample code:

echo $HOME

Output example:

/home/username

The "username" here is the actual username of the current user.

3. USER
   USER environment variable contains the user name of the currently logged in user.

Sample code:

echo $USER

Output example:

username

If the currently logged in user is "username", then the output is "username".

4. SHELL
   The SHELL environment variable specifies the Shell program used by the current user.

Sample code:

echo $SHELL

Output example:

/bin/bash

The above example indicates that the current user is using the bash shell.

5. LANG
   The LANG environment variable specifies the locale used by the current system.

Sample code:

echo $LANG

Output example:

en_US.UTF-8

This example shows that the locale used by the system is English (United States) and uses UTF-8 encoding.

Summary
Linux environment variables play a vital role in the system and can affect the running of the program and the user experience. Proficiency in the meaning and usage of commonly used environment variables can help users better understand the operating mechanism of the system. I hope the commonly used Linux environment variables introduced in this article will be helpful to readers.

The above is a detailed analysis of commonly used environment variables in Linux. I hope readers can benefit from it.

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