I am running RHEL 6, and I have exported an environment variable like this:
export DISPLAY=:0 That variable is lost when the terminal is closed. How do I permanently add this so that this variable value always exists with a particular user?
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6 Answers
You can add it to your shell configuration file, e.g., $HOME/.bashrc or more globally in /etc/environment.
After adding these lines, the changes won't reflect instantly in GUI-based systems. You have to exit the terminal or create a new one and on the server, log out the session and log in to reflect these changes.
However, you may also execute ~/.bashrc manually using the bash builtin source.
$ source ~/.bashrc For other shells, consult documentation for analogous commands.
8 Comments
Bitterblue
Thanks, that's helpful. How can I make changes take effect without restart ? (I'm Linux newbie)
kostja
@mini-me - ~/bashrc is pulled each time you open a shell. To load it explicitly, use
source e.g. - > source ~/.bashrc.
Antoine
@mini-me: the environment of a process is usually set by the caller and changed from within the process. Changing env from outside a running process is unusual and not doable with
export, but try with a debuggerAntoine
@Mr.Hyde: It usually doesn't matter. Files are parsed from top to bottom, so if a var definition depends on another, they should be ordered accordingly. So yes the end of the file is fine.
Toolkit
just note
Shell config files such as ~/.bashrc, ~/.bash_profile, and ~/.bash_login are often suggested for setting environment variables. While this may work on Bash shells for programs started from the shell, variables set in those files are not available by default to programs started from the graphical environment in a desktop session. from help.ubuntu.com/community/EnvironmentVariables |
You have to edit three files to set a permanent environment variable as follow:
~/.bashrc
When you open any terminal window this file will be run. Therefore, if you wish to have a permanent environment variable in all of your terminal windows you have to add the following line at the end of this file:
export DISPLAY=0~/.profile
Same as bashrc you have to put the mentioned command line at the end of this file to have your environment variable in every login of your OS.
/etc/environment
If you want your environment variable in every window or application (not just terminal window) you have to edit this file. Add the following command at the end of this file:
DISPLAY=0Note that in this file you do not have to write export command
Normally you have to restart your computer to apply these changes. But you can apply changes in bashrc and profile by these commands:
$ source ~/.bashrc $ source ~/.profile But for /etc/environment you have no choice but restarting (as far as I know)
A Simple Solution
I've written a simple script for these procedures to do all those work. You just have to set the name and value of your environment variable.
#!/bin/bash echo "Enter variable name: " read variable_name echo "Enter variable value: " read variable_value echo "adding " $variable_name " to environment variables: " $variable_value echo "export "$variable_name"="$variable_value>>~/.bashrc echo $variable_name"="$variable_value>>~/.profile echo $variable_name"="$variable_value>>/etc/environment source ~/.bashrc source ~/.profile echo "do you want to restart your computer to apply changes in /etc/environment file? yes(y)no(n)" read restart case $restart in y) sudo shutdown -r 0;; n) echo "don't forget to restart your computer manually";; esac exit Save these lines in a shfile then make it executable and just run it!
4 Comments
Brunno Vodola Martins
The script worked very well. I have Ubuntu 14.04 installed. I just pasted the content above in a blank file, named it insert_var.sh, then
chmod -x insert_var.sh, then bash insert_var.sh. Thanks.
vgokul129
I opened a Terminal Window in Ubuntu and enter export MY_VAR=1. Where will this Variable MY_VAR stored ?
Muhammad Tariq
Your variable
MY_VAR will only be part of the current shell that you are working on. If you close the shell, the variable will be inaccessible.
Eduardo Lúcio
I tested the approach with just the
/etc/environment file on CentOS 8 and I didn't need to restart I just needed to exit (log out) the terminal or create a new one (log in).On Ubuntu systems, use the following locations:
System-wide persistent variables in the format of
JAVA_PATH=/usr/local/javastore in/etc/environmentSystem-wide persistent variables that reference variables such as
export PATH="$JAVA_PATH:$PATH"store in/etc/.bashrcUser-specific persistent variables in the format of
PATH DEFAULT=/usr/bin:usr/local/binstore in~/.pam_environment
For more details on #2, check this Ask Ubuntu answer.
NOTE: #3 is the Ubuntu recommendation, but it may have security concerns in the real world.
Comments
Add the line to your .bashrc file or .profile.
The variables set in file $HOME/.profile are active for the current user, and the ones in /etc/profile are global. The .bashrc file is pulled on each Bash session start.
Comments
If it suits anyone, here are some brief guidelines for adding environment variables permanently.
vi ~/.bash_profile Add the variables to the file:
export DISPLAY=:0 export JAVA_HOME=~/opt/openjdk11 Immediately apply all changes:
source ~/.bash_profile 
Comments
A particular example:
I have Java 7 and Java 6 installed, I need to run some builds with 6, others with 7. Therefore I need to dynamically alter JAVA_HOME so that Maven picks up what I want for each build. I did the following:
- created
j6.shscript which simply does exportJAVA_HOME=...path to j6 install... - then, as suggested by one of the comments above, whenever I need J6 for a build, I run source
j6.shin that respective command terminal. By default, myJAVA_HOMEis set to J7.
