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?
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.
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=0
Note 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!
Add the line to your .bashrc file or .profile.
The variables set in file $HOME/.profile are active for the current user, and the ones in /etc/profile are global. The .bashrc file is pulled on each Bash session start.
On Ubuntu systems, use the following locations:
System-wide persistent variables in the format of JAVA_PATH=/usr/local/java store in
/etc/environment
System-wide persistent variables that reference variables such as
export PATH="$JAVA_PATH:$PATH" store in
/etc/.bashrc
User-specific persistent variables in the format of PATH DEFAULT=/usr/bin:usr/local/bin store in
~/.pam_environment
For more details on #2, check this
Ask Ubuntu answer.
NOTE: #3 is the Ubuntu recommendation, but it may have security concerns in the real world.
If it suits anyone, here are some brief guidelines for adding environment variables permanently.
vi ~/.bash_profile
Add the variables to the file:
export DISPLAY=:0
export JAVA_HOME=~/opt/openjdk11
Immediately apply all changes:
source ~/.bash_profile
Source: How to Set Environment Variables in Linux
A particular example:
I have Java 7 and Java 6 installed, I need to run some builds with 6, others with 7. Therefore I need to dynamically alter JAVA_HOME so that Maven picks up what I want for each build. I did the following:
created j6.sh script which simply does export JAVA_HOME=... path to j6 install...
then, as suggested by one of the comments above, whenever I need J6 for a build, I run source j6.sh in that respective command terminal. By default, my JAVA_HOME is set to J7.
I have some questions regarding the suggested setup from LFS.
Question:
what is this command really doing
cat > ~/.bash_profile << "EOF"
exec env -i HOME=$HOME TERM=$TERM PS1='\u:\w\$ ' /bin/bash
EOF
it mentions that the "new instance of the shell is a non-login shell" so we have to setup .bashrc ....however it doesn't really explains how we use this bashrc once created. It goes back to bash_profile at the end.
Most of it is well explained, but perhaps it is more technical for this section than what I expected and it also involves some important concepts I would like to understand in greater detail. I have marked in bold some commands I am unable to understand what they are doing.
From: http://www.linuxfromscratch.org/lfs/view/stable/chapter04/settingenvironment.html
Set up a good working environment by creating two new startup files for the bash shell. While logged in as user lfs, issue the following command to create a new .bash_profile:
cat > ~/.bash_profile << "EOF"
exec env -i HOME=$HOME TERM=$TERM PS1='\u:\w\$ ' /bin/bash
EOF
When logged on as user lfs, the initial shell is usually a login shell which reads the /etc/profile of the host and then .bash_profile. The exec env -i.../bin/bash command in the .bash_profile file replaces the running shell with a new one with a completely empty environment, except for the HOME, TERM, and PS1 variables. This ensures that no unwanted and potentially hazardous environment variables from the host system leak into the build environment.
The new instance of the shell is a non-login shell, which does not read the /etc/profile or .bash_profile files, but rather reads the .bashrc file instead. Create the .bashrc file now:
cat > ~/.bashrc << "EOF"
set +h
umask 022
LFS=/mnt/lfs
LC_ALL=POSIX
LFS_TGT=$(uname -m)-lfs-linux-gnu
PATH=/tools/bin:/bin:/usr/bin
export LFS LC_ALL LFS_TGT PATH
EOF
The set +h command turns off bash's hash function. Hashing is ordinarily a useful feature—bash uses a hash table to remember the full path of executable files to avoid searching the PATH time and again to find the same executable. However, the new tools should be used as soon as they are installed. By switching off the hash function, the shell will always search the PATH when a program is to be run. As such, the shell will find the newly compiled tools in $LFS/tools as soon as they are available without remembering a previous version of the same program in a different location.
Setting the user file-creation mask (umask) to 022 ensures that newly created files and directories are only writable by their owner, but are readable and executable by anyone (assuming default modes are used by the open(2) system call, new files will end up with permission mode 644 and directories with mode 755).
The LFS variable should be set to the chosen mount point.
The LC_ALL variable controls the localization of certain programs, making their messages follow the conventions of a specified country. If the host system uses a version of Glibc older than 2.2.4, having LC_ALL set to something other than “POSIX” or “C” (during this chapter) may cause issues if you exit the chroot environment and wish to return later. Setting LC_ALL to “POSIX” or “C” (the two are equivalent) ensures that everything will work as expected in the chroot environment.
The LFS_TGT variable sets a non-default, but compatible machine description for use when building our cross compiler and linker and when cross compiling our temporary toolchain. More information is contained in Section 5.2, “Toolchain Technical Notes”.
Finally, to have the environment fully prepared for building the temporary tools, source the just-created user profile:
source ~/.bash_profile
See Bash Startup Files
cat > ~/.bash_profile << "EOF" exec env -i HOME=$HOME TERM=$TERM PS1='\u:\w\$ ' /bin/bash EOF
In that, env summons a new interactive non-login bash (/bin/bash) instance with environmental variables ignored (-i) besides those set explicitly. Non-login bash instances don't read .bash_profile, .bash_login and .profile, but read .bashrc. Login instances however read those files but not .bashrc. Since env doesn't pass -l to /bin/bash, bash would not run as a login shell.
And exec overwrites the current shell process with env. env on the other hand exec's bash so it's like over-all the old shell is transformed to a new bash but the process ID would still be the same.
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On Linux, how can I add a directory to the $PATH so it remains persistent across different sessions?
Background
I'm trying to add a directory to my path so it will always be in my Linux path. I've tried:
export PATH=$PATH:/path/to/dir
This works, however each time I exit the terminal and start a new terminal instance, this path is lost, and I need to run the export command again.
How can I do it so this will be set permanently?
You need to add it to your ~/.profile or ~/.bashrc file.
export PATH="$PATH:/path/to/dir"
Depending on what you're doing, you also may want to symlink to binaries:
cd /usr/bin
sudo ln -s /path/to/binary binary-name
Note that this will not automatically update your path for the remainder of the session. To do this, you should run:
source ~/.profile
or
source ~/.bashrc
There are multiple ways to do it. The actual solution depends on the purpose.
The variable values are usually stored in either a list of assignments or a shell script that is run at the start of the system or user session. In case of the shell script you must use a specific shell syntax and export or set commands.
System wide
/etc/environment List of unique assignments. Allows references. Perfect for adding system-wide directories like /usr/local/something/bin to PATH variable or defining JAVA_HOME. Used by PAM and systemd.
/etc/environment.d/*.conf List of unique assignments. Allows references. Perfect for adding system-wide directories like /usr/local/something/bin to PATH variable or defining JAVA_HOME. The configuration can be split into multiple files, usually one per each tool (Java, Go, and Node.js). Used by systemd that by design do not pass those values to user login shells.
/etc/xprofile Shell script executed while starting X Window System session. This is run for every user that logs into X Window System. It is a good choice for PATH entries that are valid for every user like /usr/local/something/bin. The file is included by other script so use POSIX shell syntax not the syntax of your user shell.
/etc/profile and /etc/profile.d/* Shell script. This is a good choice for shell-only systems. Those files are read only by shells in login mode.
/etc/<shell>.<shell>rc. Shell script. This is a poor choice because it is single shell specific. Used in non-login mode.
User session
~/.pam_environment. List of unique assignments, no references allowed. Loaded by PAM at the start of every user session irrelevant if it is an X Window System session or shell. You cannot reference other variables including HOME or PATH so it has limited use. Used by PAM.
~/.xprofile Shell script. This is executed when the user logs into X Window System system. The variables defined here are visible to every X application. Perfect choice for extending PATH with values such as ~/bin or ~/go/bin or defining user specific GOPATH or NPM_HOME. The file is included by other script so use POSIX shell syntax not the syntax of your user shell. Your graphical text editor or IDE started by shortcut will see those values.
~/.profile, ~/.<shell>_profile, ~/.<shell>_login Shell script. It will be visible only for programs started from terminal or terminal emulator. It is a good choice for shell-only systems. Used by shells in login mode.
~/.<shell>rc. Shell script. This is a poor choice because it is single shell specific. Used by shells in non-login mode.
Notes
GNOME on Wayland starts a user login shell to get the environment. It effectively uses the login shell configurations ~/.profile, ~/.<shell>_profile, ~/.<shell>_login files.
Man pages
environment
environment.d https://linux.die.net/man/1/environment.d
bash
dash
Distribution-specific documentation
Ubuntu
Arch Linux
Related
Difference between Login Shell and Non-Login Shell?
In Ubuntu, edit /etc/environment. Its sole purpose is to store environment variables. Originally the $PATH variable is defined here.
This is a paste from my /etc/environment file:
PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games"
So you can just open up this file as root and add whatever you want.
For immediate results,
Run (try as normal user and root):
source /etc/environment && export PATH
If you use Z shell (zsh), add this line right after the comments in /etc/zsh/zshenv file:
source /etc/environment
I encountered this little quirk on Ubuntu 15.10 (Wily Werewolf), but if your zsh is not getting the correct PATH, this could be why.
For Bash, you can put the export declaration in ~/.bashrc. For example, my .bashrc contains this line:
export PATH=/var/lib/gems/1.8/bin:/home/ash/.bin:$PATH
You may set $PATH permanently in two ways.
To set the path for a particular user:
You may need to make the entry in file .bash_profile in the home directory for the user.
E.g, in my case I will set the java path in the Tomcat user profile*
echo "export PATH=$PATH:/path/to/dir" >> /home/tomcat/.bash_profile
To set a common path for all system users, you may need to set the path like this:
echo "export PATH=$PATH:/path/to/dir" >> /etc/profile
You can use on CentOS or Red Hat Linux (RHEL) for the local user:
echo $"export PATH=\$PATH:$(pwd)" >> ~/.bash_profile
This adds the current directory (or you can use another directory) to the PATH. This makes it permanent, but it takes effect at the next user logon.
If you don't want do a re-logon, then you can use:
source ~/.bash_profile
That reloads the # User specific environment and startup programs. This comment is present in file .bash_profile.
You can also set it permanently, editing one of these files:
/etc/profile (for all users)
~/.bash_profile (for current user)
~/.bash_login (for current user)
~/.profile (for current user)
You can also use /etc/environment to set a permanent PATH environment variable, but it does not support variable expansion.
Extracted from: Linux: Añadir ruta al PATH
I think the most elegant way is:
Add this in the ~/.bashrc file.
Run this command:
gedit ~/.bashrc
Add your path inside it:
export PATH=$PATH:/opt/node/bin
source ~/.bashrc
(Ubuntu)
Modify the "/etc/profile" file:
vi /etc/profile
Press the I key to enter editing mode and move the cursor to the end of the file. Additional entries：
export PATH=$PATH:/path/to/dir;
Press the Esc key to exit edit mode, and :wq to save the file.
Make the configuration effective
source /etc/profile
Explanation：
The profile file works for all users. If you want it to be valid only for the active user, change the ".bashrc" file.
I stumbled across this question yesterday when searching for a way to add a folder containing my own scripts to the PATH - and was surprised to find out that my own ~/.profile file (on Linux Mint 18.1) already contained this:
# set PATH so it includes user's private bin if it exists
if [ -d "$HOME/bin" ] ; then
PATH="$HOME/bin:$PATH"
fi
Thus, all I had to do was create the folder ~/bin and put my scripts there.
You can add that line to your console configuration files (e.g., .bashrc, or to .profile).
After so much research, I found a simple solution for this (I am using Elementary OS), inspired by Flutter – Step by Step Installation on Linux – Ubuntu.
Run the following command to open the .bashrc file in edit mode. (You
may also use vi or any other editor).
~$ sudo nano ~/.bashrc
Add the following line at the end of the file and save.
export PATH="[FLUTTER_SDK_PATH]/flutter/bin:$PATH"
For example:
export PATH="/home/rageshl/dev/flutter/bin:$PATH"
I believe this is the permanent solution for setting the path in Flutter in a Ubuntu distribution.
It can be directly added by using the following command:
echo 'export PATH=$PATH:/new/directory' >> ~/.zshrc
source ~/.zshrc
One way to add a permanent path, which worked for me, is:
cd /etc/profile.d
touch custom.sh
vi custom.sh
export PATH=$PATH:/path according to your setting/
Restart your computer and here we go; the path will be there permanently.
Add script file [name_of_script].sh to the /etc/profile.d folder with the line:
export PATH=$PATH:/dir
Every script within the /etc/profile.d folder is automatically executed by /etc/profile on login.
My answer is in reference to the setting up of a Go environment on Ubuntu Linux (amd64). I have faced the same trouble of setting the path of environment variables (GOPATH and GOBIN), losing it on terminal exit and rebuilding it using the source <file_name> every time.
The mistake was to put the path (GOPATH and GOBIN) in ~/.bash_profile file. After wasting a few good hours, I found that the solution was to put GOPATH and GOBIN in the ~/.bash_rc file in the manner:
export GOPATH=$HOME/go
export GOBIN=$GOPATH/bin
export PATH=$PATH:$GOPATH:$GOBIN
And in doing so, the Go installation worked fine and there were no path losses.
The reason with which this issue can be related is that settings for non-login shells, like your Ubuntu terminal or GNOME terminal where we run the Go code, are taken from the ~./bash_rc file and the settings for login shells are taken from ~/.bash_profile file. And from the ~/.profile file if the ~/.bash_profile file is unreachable.
The files where you add the export command depends on if you are in login-mode or non-login-mode.
If you are in login-mode, the files you are looking for are either /etc/bash or /etc/bash.bashrc.
If you are in non-login-mode, you are looking for the file /.profile or for the files within the directory /.profiles.d
The files mentioned above is where the system variables are.
Permanently add to the PATH variable
Global:
echo "export PATH=$PATH:/new/path/variable" >> /etc/profile
Local (for the current user only):
echo "export PATH=$PATH:/new/path/variable" >> ~/.profile
For global, restart. For local, relogin.
Example
Before:
$ cat /etc/profile
#!/bin/sh
export PATH=/usr/bin:/usr/sbin:/bin:/sbin
After:
$ cat /etc/profile
#!/bin/sh
export PATH=/usr/bin:/usr/sbin:/bin:/sbin
export PATH=/usr/bin:/usr/sbin:/bin:/sbin:/new/path/variable
Alternatively you can just edit file "profile":
$ cat /etc/profile
#!/bin/sh
export PATH=/usr/bin:/usr/sbin:/bin:/sbin:/new/path/variable
Another way (thanks gniourf_gniourf):
echo 'PATH=$PATH:/new/path/variable' >> /etc/profile
You shouldn't use double quotes here! echo 'export
PATH=$PATH:/new/path/variable'... And by the way, the export keyword
is very likely useless as the PATH variable is very likely already
marked as exported. – gniourf_gniourf
Zues77 has the right idea. The OP didn't say "How can I hack my way through this?". The OP wanted to know how to permanently append to $PATH:
sudo nano /etc/profile
This is where it is set for everything and is the best place to change it for all things needing $PATH.
Let's say you're running macOS. You have a binary you trust and would like to make available across your system, but don't necessarily want the directory in which the binary is to be added to your PATH.
You can opt to copy/move the binary to /usr/local/bin, which should already be in your PATH. This will make the binary executable like any other binary you may already have access to in your terminal.
The simplest way is the following line,
PATH="<directory you want to include>:$PATH"
in your .bashrc file in the home directory.
It will not get reset even if you close the terminal or reboot your PC. It's permanent.
This is a one-liner. It adds a line to the .bashrc. That line is going to check if the directory has already been added to the path and append if not. This will prevent duplicating your directory in the path every time you source .bashrc.
echo "[[ \":\$PATH:\" != *\":$(pwd)/path/to/add:\"* ]] && export PATH=\"\${PATH:+\${PATH}}:$(pwd)/path/to/add\"" >> ~/.bashrc
source ~/.bashrc
I think the most elegant way is:
Add this in the ~./bashrc file:
if [ -d "new-path" ]; then
PATH=$PATH:new-path
fi
source *~/.bashrc*
(Ubuntu)
For a Debian distribution, you have to:
edit file ~/.bashrc. E.g: vim ~/.bashrc
add export PATH=$PATH:/path/to/dir
then restart your computer. Be aware that if you edit file ~/.bashrc as root, your environment variable you added will work only for root
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?
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.
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=0
Note 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!
Add the line to your .bashrc file or .profile.
The variables set in file $HOME/.profile are active for the current user, and the ones in /etc/profile are global. The .bashrc file is pulled on each Bash session start.
On Ubuntu systems, use the following locations:
System-wide persistent variables in the format of JAVA_PATH=/usr/local/java store in
/etc/environment
System-wide persistent variables that reference variables such as
export PATH="$JAVA_PATH:$PATH" store in
/etc/.bashrc
User-specific persistent variables in the format of PATH DEFAULT=/usr/bin:usr/local/bin store 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.
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
Source: How to Set Environment Variables in Linux
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.sh script which simply does export JAVA_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.sh in that respective command terminal. By default, my JAVA_HOME is set to J7.