How to modify environment variables in Linux operating system

Method 1: Add variables to the /etc/profile file [Effective for all users (permanent)]

Use vi to add variables to the file /etc/profile file. This variable will be valid for all users under Linux and is "permanent".

To make the modification take effect immediately, you need to execute the following code

Copy the code The code is as follows:

# source /etc/profile

Method 2: Add variables to the .bash_profile file in the user directory [Effective for a single user (permanent)]

Use vi to add variables to the .bash_profile file in the user directory. Changes are only effective for the current user and are "permanent".

To make the modification take effect immediately, you need to execute the following code in the user directory

Copy the code The code is as follows:

# source .bash_profile

Method 3: Directly run the export command to define variables [valid only for the current shell (bash) (temporary)]

Directly use [export variable name= on the shell command line Variable value] defines a variable. This variable is only valid under the current shell (bash) or its subshell (bash). When the shell is closed, the variable will become invalid. When you open a new shell, there will be no such variable. You need to use needs to be redefined.

Method 4: Direct assignment

Enter

in the command line to copy the code. The code is as follows:

path=$path: /usr/lib64/ruby/gems/2.1.0/gems/jekyll-2.5.3/bin

Using this method is only valid for the current session, that is, whenever you log out or After logging out of the system, the path settings will become invalid.

Method Five: Modify the /ect/profile file

Add

Copy code at the end of the file The code is as follows:

export path =$path:/usr/lib64/ruby/gems/2.1.0/gems/jekyll-2.5.3/bin

//Note: There cannot be any spaces on both sides of the "=" sign. This method is the best, unless

you forcefully modify the path value manually, otherwise it will not be changed.

Method 6: Modify the .bachrc/.bash_profile file

Add

Copy code at the end of the file The code is as follows:

export path=$path:/usr/lib64/ruby/gems/2.1.0/gems/jekyll-2.5.3/bin

This method works for the current user. It will also become invalid when you log out of the system

Note: For methods 2 and 3, if you want the path to take effect, you must log in again. The following method can simplify the work: If /etc/profile is modified, then the editing is completed Then execute the source profile or execute the command ./profile path and the value of the path will take effect immediately. The principle of this method is to execute the /etc/profile shell script again. Note that it will not work if you use sh /etc/profile, because sh is executed in a subshell process, and even if the path changes, it will not be reflected in the current environment. , but source is executed in the current shell process, so we can see the path change.

The above is the detailed content of How to modify environment variables in Linux operating system. For more information, please follow other related articles on the PHP Chinese website!