I am trying to set up Java in my new laptop. I have installed java jdk and I am trying to set up the environment variable now, But I am really confused between the file .bash_profile, .bashrc, .profile. I understand the concept behind login and non login shells, but when I wrote the JAVA_HOME, PATH variable in .bash_profile I needed to manually run the command
. .bash_profile
It did not get executed at the start when I restarted the computer to make it run as .bash_profile is supposed to be called by login shells. Can anyone explain to me what is the reason behind .bash_profile not being called up?
Since .bash_profile was not being called, I decide to type the PATH, JAVA_HOME variable to the file .bashrc, While this is working is this the right way to set up environment variables?
Related
I need to create an environment variable that is set within a bash script. I want this environment variable to be a system wide environment variable and I also want to be able to use it in an if condition in rc.local. So far I have tried /etc/profile but rc.local does not see it when I set it there.
Which script should I set this environment variable in so that rc.local can see it when I boot?
Other question while I’m at it. Who starts rc.local?
Cheers,
Dave
Rc.local runs before the operating system is fully booted but has not yet started the login shell, so the environment variables we configured in /etc/profiles or bashrc are not executed, so no environment variables are visible during the rc.local implementation phase.
The solution is:
Add export ENVNAME=*********** before the command in rc.local
I am trying to run the Swift compiler under Ubuntu. I followed this tutorial: https://itsfoss.com/use-swift-linux/ and everything seemed to work fine. I was able to run swift under Ubuntu.
However, when I closed the terminal, I was not able to run Swift anymore. The program was not found until I installed it again. I could not find any answers to this question as there aren't many people running Swift under Ubuntu.
It's not uninstalled, you just don't have the environment variables set up anymore, so Bash can't find the path to Swift. You can change that by exporting the appropriate environment variables in your .bashrc file.
When you followed the tutorial, you ran the following command:
export PATH=path_to_swift_usr_bin:$PATH
This command adds the path to the swift binary to your PATH environment variable. The PATH variable holds a list of places where Ubuntu will look for programs to run from the command-line. So if the Swift executable is not in one of the places listed in the PATH, your terminal will never find it.
There is a file in your home folder (the folder ~, which is an abbreviation for /home/username, where username is your username) named .bashrc, which runs whenever you open a new terminal window. If you need an environment variable to be available whenever you open the terminal, you should add the export line for that variable to your .bashrc.
In this case, your .basrhc should contain the same line above.
The important thing to remember is that your environment variables are not preserved between command-line sessions, so if you want to have an environment variable available every time you use the command-line, it needs to be defined in your .bashrc.
The JAVA_HOME environment variable is not defined
This environment variable is needed to run this program.
How to fix in ubuntu 12.04?
probably more a question for http://ubuntuforums.org/
That said, you can do:
export JAVA_HOME='path/to/your/java/installation'
and add the same line to your .bashrc file to have it done every time you log in.
Beware, usually if you install java using apt-get, you should not have to set the java_home environmnent variable.
everyone.
I had a basic question want to consult, about the environment variable setting.
After closed my one existed terminal which could execute compile(make) and do customed(mksdboot) command, i can't do mksdboot command anymore(I had execute a predefined setting environment variable shell script i.e. $ . ./arndale_envsetup.sh again) in the new terminal.
Cause i am a beginner in Linux, i am not very clearly about the environment variable setting rules.
i had tried to 'su' or 'sudo' to execute mksdboot, but no luck:(
ps. I had another project needs to compile in my PC(i didn't export PATH to .bashrc, only execute export PATH when i open a new terminal every time), may it efforts the original project's environment variable?
thanks.
[UPDATED]
i tried using $source ./arndale_envsetup.sh, relative commands worked finally.
but i still did't figure out the reason between work or not work. >"<
The command
history
will list what your previous commands where.
This might give you a pointer what set the path in the way you needed it.
You could also try to see where you command is via
locate mksdboot
i have trying to use some global variable in my ant file.
when i do login through terminal. i can access those variable like JAVA_HOME
but when i am trying to access variable through the ant command i am not able to find them.
global variable declared in .cshrc
setenv JAVA_HOME jdk_full_path
ant code using variable.
<property environment="env"/>
<property name="ear" value= "true"/>
<property name="home" value="${env.HOME}"/>
<property name="java_home" value="${env.JAVA_HOME}"/>
i can access home variable but i am not able to find JAVA_HOME variable ,i am executing this ant through eclipse
Please suggest me where should i declare the variable so i can access them
The problem is probably that Eclipse doesn't have JAVA_HOME in its environment.
Try logging out and back in again, then run Eclipse.
Alternatively, open a terminal, and run Eclipse from there.
The .cshrc file is only run when you start a new C shell, it is not for global variables. Since you are not starting Eclipse from the C shell it will not see any variables you set there.
Try the ~/.login file or the /etc/profile file in case eclipse starts up using bash. Both of these files are only loaded once when the user logs on so they should effect everything. You may require a restart or even a reboot for changes to these files to take effect.
Environment variables are inherited through process execution, they are not global. So, when you edit your shell's RC file to add a variable, it only takes effect for shells executed AFTER that modification, and for programs executed from those shells. If you started Eclipse from KDE/Gnome, and KDE/Gnome was started before you made that change, then KDE/Gnome never had the definition and therefore Eclipse did not either.
I recommend logging out and back in. Also, depending on your default shell setting, you may find that KDE/Gnome is being started through bash or something else, meaning that you'll need to modify .bashrc instead of .cshrc.
You should define this variables at one of the following files:
~/.profile or ~/.bash_profile runs only with login shells i.e when you first log in into system.
~/.bashrc file runs every time you open a new non-login bash shell such as xterm
So, you should add to this files the line:
export JAVA_HOME=jdk_full_path
You must re-login for the changes take efect