How to set PATH in Knoppix? - linux

I'm using knoppix 7.0.3 and trying to set the PATH environment variable. According to the official Ubuntu documentation, /etc/environment should be the preferred place for this. So I added these lines in the file:
JAVA_HOME="/usr/lib/jvm/java-6-sun"
GRAILS_HOME="/home/knoppix/grails"
PATH="${PATH}:${JAVA_HOME}/bin:${GRAILS_HOME}/bin"
But after rebooting the system, the file just reverted to the original one (I was using persistent storage).
Then after some Googling, I tried to edit ~/.profile like this:
export JAVA_HOME="/usr/lib/jvm/java-6-sun"
export GRAILS_HOME="/home/knoppix/grails"
export PATH=$PATH:$JAVA_HOME/bin:$GRAILS_HOME/bin
This time, the first two variables got set (echoed in console), but the PATH didn't. It was still the default one when I echoed. What's wrong?

Modify /etc/profile on the following line:
PATH=".:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games"

The problem is that your PATH is being overwritten during initialization of bash, after reading .profile.
From the manpage of bash:
When bash is invoked as an interactive login shell, or as a non-interactive shell with the --login option, it first reads and executes commands from the file /etc/profile, if that file exists. After reading that file, it looks for ~/.bash_profile, ~/.bash_login, and ~/.profile, in that order, and reads and executes commands from the first one that exists and is readable. The --noprofile option may be used when the shell is started to inhibit this behavior.
...
When an interactive shell that is not a login shell is started, bash reads and executes commands from ~/.bashrc, if that file exists. This may be inhibited by using the --norc option. The --rcfile file option will force bash to read and execute commands from file instead of ~/.bashrc.
From your experience, it is apparent that if .bashrc doesn't exist, bash is trying to set PATH to a default value (I would appreciate if someone confirms this).
As we discussed in the comments on your question, adding the export commands to .bashrc (and thus creating the file) solves the problem. Alternatively, you can add
source ~/.profile
to the end of your .bashrc file for the same effect.

Related

My alias name is referring to old alias not a new one [duplicate]

This question already has answers here:
Closed 10 years ago.
Possible Duplicate:
What's the difference between .bashrc, .bash_profile, and .environment?
It seems that if I use
alias ls='ls -F'
inside of .bashrc on Mac OS X, then the newly created shell will not have that alias. I need to type bash again and that alias will be in effect.
And if I log into Linux on the hosting company, the .bashrc file has a comment line that says:
For non-login shell
and the .bash_profile file has a comment that says
for login shell
So where should aliases be written in? How come we separate the login shell and non-login shell?
Some webpage say use .bash_aliases, but it doesn't work on Mac OS X, it seems.
The reason you separate the login and non-login shell is because the .bashrc file is reloaded every time you start a new copy of Bash. The .profile file is loaded only when you either log in or use the appropriate flag to tell Bash to act as a login shell.
Personally,
I put my PATH setup into a .profile file (because I sometimes use other shells);
I put my Bash aliases and functions into my .bashrc file;
I put this
#!/bin/bash
#
# CRM .bash_profile Time-stamp: "2008-12-07 19:42"
#
# echo "Loading ${HOME}/.bash_profile"
source ~/.profile # get my PATH setup
source ~/.bashrc # get my Bash aliases
in my .bash_profile file.
Oh, and the reason you need to type bash again to get the new alias is that Bash loads your .bashrc file when it starts but it doesn't reload it unless you tell it to. You can reload the .bashrc file (and not need a second shell) by typing
source ~/.bashrc
which loads the .bashrc file as if you had typed the commands directly to Bash.
Check out http://mywiki.wooledge.org/DotFiles for an excellent resource on the topic aside from man bash.
Summary:
You only log in once, and that's when ~/.bash_profile or ~/.profile is read and executed. Since everything you run from your login shell inherits the login shell's environment, you should put all your environment variables in there. Like LESS, PATH, MANPATH, LC_*, ... For an example, see: My .profile
Once you log in, you can run several more shells. Imagine logging in, running X, and in X starting a few terminals with bash shells. That means your login shell started X, which inherited your login shell's environment variables, which started your terminals, which started your non-login bash shells. Your environment variables were passed along in the whole chain, so your non-login shells don't need to load them anymore. Non-login shells only execute ~/.bashrc, not /.profile or ~/.bash_profile, for this exact reason, so in there define everything that only applies to bash. That's functions, aliases, bash-only variables like HISTSIZE (this is not an environment variable, don't export it!), shell options with set and shopt, etc. For an example, see: My .bashrc
Now, as part of UNIX peculiarity, a login-shell does NOT execute ~/.bashrc but only ~/.profile or ~/.bash_profile, so you should source that one manually from the latter. You'll see me do that in my ~/.profile too: source ~/.bashrc.
From the bash manpage:
When bash is invoked as an
interactive login shell, or as a
non-interactive shell with the
--login option, it first reads and executes commands from the file
/etc/profile, if that file exists.
After reading that file, it looks for
~/.bash_profile, ~/.bash_login, and
~/.profile, in that order, and reads
and executes commands from the first
one that exists and is readable. The
--noprofile option may be used when the shell is started to inhibit this
behavior.
When a login shell exits, bash
reads and executes commands from the
file ~/.bash_logout, if it exists.
When an interactive shell that is not a login shell is started, bash
reads and executes commands from ~/.bashrc, if that file exists. This
may be inhibited by using the --norc option. The --rcfile file option
will force bash to read and execute commands from file instead of
~/.bashrc.
Thus, if you want to get the same behavior for both login shells and interactive non-login shells, you should put all of your commands in either .bashrc or .bash_profile, and then have the other file source the first one.
.bash_profile is loaded for a "login shell". I am not sure what that would be on OS X, but on Linux that is either X11 or a virtual terminal.
.bashrc is loaded every time you run Bash. That is where you should put stuff you want loaded whenever you open a new Terminal.app window.
I personally put everything in .bashrc so that I don't have to restart the application for changes to take effect.

Sourcing from a different bashrc

My original .bashrc script is currently used to run model runs. Now I need to manipulate it to compile a completely new model.
My question is, if I save my original .bashrc, as something such as .bwwbashrc, do I need to manipulate the file in some way so it is able to be read or recognized as the .bashrc when I source it within my scripts?
original sourcing
source /home/tsee/.bashrc
What I think the new sourcing would be.
(after creating .bwwbashrc)
source /home/tsee/.bwwbashrc
Just not sure if I need to save it with a certain extension or edit the executable in some sort of way.
Nope, you can name it whatever you want. Executable bit isn't required either.
If you aren't aware of it, the bash --login option might be of interest to you.
To complement Matt’s correct answer, I’d also point out that you can start a new Bash shell that sources your alternative file instead of .bashrc at start-up.
bash --rcfile .bwwbashrc
From the bash man page:
--rcfile file
Execute commands from file instead of the standard personal initialization
file ~/.bashrc if the shell is interactive (see INVOCATION below).
If you want to replace your current shell (with commands and settings from .bashrc), you can run
exec bash --rcfile .bwwbashrc

Where is the bash_profile in SUSE Linux

I could not find the my bash profile which running automatically after login.
I already checked /home/(username) with ls -a.
I am sure there is bash profile because when i echo $somethings, it response.
Could you help me ?
Check for ~/.bash_profile, ~/.bash_login, ~/.profile or even maybe ~/.bashrc, which isn't a "profile", but might be run after login (see INVOCATION in man bash to understand when and in what order bash reads its startup files). If the file doesn't exist, you can create it.
There're also the system-wide /etc/profile and /etc/bash.bashrc.
After /etc/profile, the bash shell (assuming it's either an interactive login shell or run with the --login option) looks for the first file in this set (in your home directory) that exists and is readable:
~/.bash_profile;
~/.bash_login; and
~/.profile.
Hence you may not even have a .bash_profile.
The rules are actually very complex, depending on the type of the shell and the various arguments you give to it. If you want to know in detail, have a look in the INVOCATION section of the bash man page.

Setting of Environmental Variables which persist in Linux

I have added the following:
export SQOOP_HOME=/usr/bin/
to my /etc/profile file. However when I run an install.sh script it keeps saying the environment variable is not set. I have also added similar lines to the bash_profile.
Any ideas what I could be doing wrong?
When running a shell script, it runs (by default) non-login and non-interactive--see my answer to another question on Unix.SE for a rundown of when and where bash looks for config files. You will probably want to add the -l option to the shebang line to make it a login shell.
You need to do a login before you can see the changes in /etc/profile. Try:
bash -l
for example.

Profile is not loaded for all the users

I recently got arm-linux-gcc toolchain up and running for my Ubuntu OS. I have configure the path variable for the toolchain in /etc/profile file. I am able to access the toolchain only when I am logged in as root and that too, I have to do
source /etc/profile
in every session. Why does this happen? why am I not able to access the toolchain from normal login.
Regards,
Probably you're not running a login-shell.
It depends a bit on the shell you're using. I use Bash, but maybe you use BusyBox?
From the bash manual:
When bash is invoked as an interactive
login shell, or as a non-interactive
shell with the --login option, it
first reads and executes commands
from the file /etc/profile, if that
file exists. After reading that file,
it looks for ~/.bash_profile,
~/.bash_login, and ~/.profile, in that
order, and reads and executes commands from the first one that
exists and is readable.
What I usually do to resolve this issue, is put:
source /etc/profile
as first line in my ~/.bashrc.
This works because ~/.bashrc is also executed for non-login shells.
To see which files are executed, you might want to put diagnostic messages in them. If I can't remember which files are executed at what type I login, I put:
echo /etc/profile/
as first line in my /etc/profile, the same for /etc/bash/bashrc, ~/.bashrc, ~/.profile and so on.
For more info, consult the "INVOCATION" part of the bash-manual.

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