I am using AWS EC2 along with the CodeStar services.
I wanted to add the path to maven's binary to the PATH environment variable.
So I wrote it to the /etc/environment file and executed the command:
source /etc/environment
But it has now changed the default environment of the bash shell and now I am not able to execute any command. Even for a command like ls it gives output -bash: command not found
How do I revert back to the default settings. I tried whatever my brain could think of. But nothing helped. Would be glad to hear from the community.
In order to revert back to the default settings:
As #Cyrus wrote you should update the PATH variable
In the bash shell run the following command:
PATH="/usr/local/bin:/bin:/usr/bin:/usr/local/sbin:/usr/sbin:/sbin"
Undo the changes to the /etc/environment
edit the /etc/environment using the same method you used before, and remove the PATH line you added to the file
You can use sudo vi /etc/environment or any other editor you prefer
Note: In my AWS machine, the /etc/environment file is empty.
I have been trying to set the $PATH environment variable to point to different paths as I need them, but I have run into some issues.
The main thing is that when I set the PATH to point to my service that I need, I want it to stay that way in all subsequent bash shells. That is, when I open another bash shell it will be set there as well, until I decide to switch it back. And when I switch the PATH back to its original value. I want it to stay that way.
I added a small script to my .bashrc, I also tried doing a separate script that will change environment variables. But the problem stays: If I open a new bash shell, it inherits the default environment variables and the default PATH.
I am setting those to enable the use of a daemon service. I tried turning on/off the service itself. That does not work because the paths have to be changed or else the shell would try to use those environment paths, but the service being off it will just hang.
I tried running a small C program wrapper to do those things but I ran into the same issue.
In order for environment variable to exist across shell sessions you will need to place those variables into a shell configuration file. This is usually done in either ~/.bashrc or ~/.profile (if you are using Bash). For example, in my ~/.profile file I have:
export PATH=/opt/local/bin:/opt/local/sbin:$PATH
I can add to that path as much as I want. The $PATH variable at the end will append whatever is current in the path.
If you need scripts to be able to access the variables, you should put the PATH into the .bashrc file. (what is the difference between .bashrc and .profile)
If you make a change to one of your shell configuration files, the changes will not be in effect until those files are used again. Those files are only used when the shell is first initialized. In order to make changes take effect, you need to log out and back in, or open a new shell and close the old, or source the file that you made changes to.
$ vim ~/.bashrc (edit the file)
$ source ~/.bashrc (then reinitialize the shell with the file)
If you only need a variable to be available in the current shell and any subprocesses, using export would be all you need.
You might also be interested in this snippet. It reloads the .bashrc in any shell, whenever it is modified. (After re-editing the .bashrc file, press (or run a command) to cause the new .bashrc to be reloaded.)
# Make sure our version of the .bashrc file is up-to-date, or reload it.
chk_bashrc_timestamp () {
if [[ "$_BASHRC_TIMESTAMP" -lt "$(get_file_timestamp "$HOME/.bashrc")" ]]; then
echo >&2 "Reloading .bashrc..."
. ~/.bashrc
fi
}
_BASHRC_TIMESTAMP=$(date +%s)
PROMPT_COMMAND=chk_bashrc_timestamp
The only difficulty is, you must not use $PATH in the definition of PATH, or it will repeat the whole PATH each time it is needed:
Use
SYSPATH="/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin:/usr/local/sbin"
PATH="$HOME/bin:$SYSPATH:/opt/mystuff"
instead of
PATH="$HOME/bin:$PATH:/opt/mystuff"
I have used this with much satisfaction in my own .bashrc, except that I have protected my PATH from reloading each time by setting it in an if statement. (You may find you have other things you need to protect this way.)
if _BASHRC_WAS_RUN 2>/dev/null; then
:;
else # Stuff that only needs to run the first time we source .bashrc.
# Useful to allow resourcing new changes
export PATH="$HOME/bin:$HOME/.cabal/bin: ..."
alias _BASHRC_WAS_RUN=true
fi
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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.
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In Ubuntu, I'd like to switch my JAVA_HOME environment variable back and forth between Java 5 and 6.
I open a terminal and type in the following to set the JAVA_HOME environment variable:
export JAVA_HOME=/usr/lib/jvm/java-1.5.0-sun
And in that same terminal window, I type the following to check that the environment variable has been updated:
echo $JAVA_HOME
And I see /usr/lib/jvm/java-1.5.0-sun which is what I'm expecting to see. In addition, I modify ~/.profile and set the JAVA_HOME environment variable to /usr/lib/jvm/java-1.5.0-sun.
And now for the problem--when I open a new terminal window and I check my JAVA_HOME environment variable by typing in echo $JAVA_HOME I see that my JAVA_HOME environment variable has been reverted back to Java 6. When I reboot my machine (or log out and back in, I suppose) the JAVA_HOME environment variable is set to Java 5 (presumably because of the modification I made in my ~/.profile).
Is there a way around this so that I can change my JAVA_HOME environment without having to log out and back in (AND make that environment variable change stick in all new terminal windows)?
Put the environment variables into the global /etc/environment file:
...
export JAVA_HOME=/usr/lib/jvm/java-1.5.0-sun
...
Execute "source /etc/environment" in every shell where you want the variables to be updated:
$ source /etc/environment
Check that it works:
$ echo $JAVA_HOME
$ /usr/lib/jvm/java-1.5.0-sun
Great, no logout needed.
If you want to set JAVA_HOME environment variable in only the terminal, set it in ~/.bashrc file.
This will probably solve your problem:
https://help.ubuntu.com/community/EnvironmentVariables
Session-wide environment variables
In order to set environment variables in a way that affects a particular user's environment, one should not place commands to set their values in particular shell script files in the user's home directory, but use:
~/.pam_environment - This file is specifically meant for setting a user's environment. It is not a script file, but rather consists of assignment expressions, one per line.
Not recommended:
~/.profile - This is probably the best file for placing environment variable assignments in, since it gets executed automatically by the DisplayManager during the startup process desktop session as well as by the login shell when one logs-in from the textual console.
Try these steps.
--We are going to edit "etc\profile".
The environment variables are to be input at the bottom of the file. Since Ubuntu does not
give access to root folder, we will have to use a few commands in the terminal
Step1: Start Terminal. Type in command: gksudo gedit /etc/profile
Step2: The profile text file will open. Enter the environment variables at the bottom of the page........... Eg: export JAVA_HOME=/home/alex/jdk1.6.0_22/bin/java
export PATH=/home/alex/jdk1.6.0_22/bin:$PATH
step3: save and close the file. Check if the environment variables are set by using echo command........ Eg echo $PATH
You need to put variable definition in the ~/.bashrc file.
From bash man page:
When an interactive shell that is
not a login shell is started, bash
reads and executes commands from
/etc/bash.bashrc and ~/.bashrc, if
these files exist.
Traditionally, if you only want to change the variable in your terminal windows, set it in .bashrc file, which is sourced each time a new terminal is opened. .profile file is not sourced each time you open a new terminal.
See the difference between .profile and .bashrc in question:
What's the difference between .bashrc, .bash_profile, and .environment?
.bashrc should solve your problem. However, it is not the proper solution since you are using Ubuntu. See the relevant Ubuntu help page "Session-wide environment variables". Thus, no wonder that .profile does not work for you. I use Ubuntu 12.04 and xfce. I set up my .profile and it is simply not taking effect even if I log out and in. Similar experience here. So you may have to use .pam_environment file and totally forget about .profile, and .bashrc. And NOTE that .pam_environment is not a script file.
Take a look at bash(1), you need a login shell to pickup the ~/.profile, i.e. the -l option.
I know this is a long cold question, but it comes up every time there is a new or recent major Java release. Now this would easily apply to 6 and 7 swapping.
I have done this in the past with update-java-alternatives:
http://manpages.ubuntu.com/manpages/hardy/man8/update-java-alternatives.8.html
After making changes to .profile, you need to execute the file, in order for the changes to take effect.
root#masternode# . ~/.profile
Once this is done, the echo command will work.