The environment-variables tag has no wiki summary.
31
votes
1answer
2k views
VISUAL vs EDITOR what's the difference?
I generally set both VISUAL and EDITOR environment variables to the same thing, but what's the difference? why would I set them differently? when developing apps why should I choose to look at VISUAL ...
29
votes
4answers
36k views
How to correctly add a path to PATH?
I'm wondering where a new path has to be added to PATH environment variable. I know this is accomplished editing .bash_rc (for example), but it's not clear how to do this.
This way:
export ...
23
votes
2answers
1k views
$VAR vs ${VAR} and to quote or not to quote
I can write
VAR=$VAR1
VAR=${VAR1}
VAR="$VAR1"
VAR="${VAR1}"
the end result to me all seems about the same. Why should I write one or the other? are any of these not portable/POSIX?
18
votes
4answers
1k views
Alternative to .bashrc
Is ~/.bashrc the only place where I can specify user specific ENV Variables, aliases, modifications to PATH variable, etc?
I ask because it seems that ~/.bashrc would be bash only...
17
votes
4answers
5k views
Why is `while IFS= read` used so often, instead of `IFS=; while read..`?
It seems that normal practice would put the setting of IFS outside the while loop in order to not repeat setting it for each iteration... Is this just a habitual "monkey see, monkey do" style, as it ...
15
votes
5answers
423 views
How to determine where an environment variable came from
I have a linux instance that I set up some time ago. When I fire it up and log in as root there are some environment variables that I set up but I can't remember or find where they came from. I've ...
14
votes
3answers
3k views
How does /usr/bin/env know which program to use?
When I use the shebang #!/usr/bin/env python to run a script, how does the system know which python to use? if I look for a python bin path in the environment variables I find nothing.
env | grep -i ...
13
votes
5answers
7k views
How can I run a script immediately after connecting via SSH?
I started to ask this question but answered it while I had it open. I'm going to post this question, follow it up with my solution and leave it open to other potential solutions.
<backstory>
...
12
votes
3answers
3k views
How to print all environment variables defined (but not necessarily exported) in bash
The bash builtin command set, if invoked without arguments, will print all environment variables, but also all defined functions. this makes the output unusable for humans and difficult to grep.
How ...
11
votes
4answers
28k views
How do I set a user environment variable? (permanently, not session)
This is irritating me. I seen several suggestions (all using different files and syntax) and none of them worked.
How do I set an environment variable for a specific user? I am on debian squeeze.
...
11
votes
1answer
2k views
Difference between environment variables and exported environment variables in bash
Bash seems to differentiate between variables which have been exported and those which have not.
example:
$ FOO=BAR
$ env | grep FOO
$ set | grep FOO
FOO=BAR
set sees the variable but env does ...
10
votes
4answers
541 views
keep duplicates out of $PATH on source
I have the following code that's source-d by my .shellrc
PATH="${PATH}:${HOME}/perl5/bin"
PATH="${PATH}:${HOME}/.bin"
export PATH
but if I make changes to other code and then source this file, my ...
9
votes
4answers
2k views
Script to change current directory (cd, pwd)
I want to run a script to simply change the current working directory:
#!/bin/bash
cd web/www/project
But, after I run it, the current pwd remains unchanged! How can I do that?
9
votes
2answers
1k views
How do I change the default text editor in the Debian (squeeze) distro
"Joe's own editor" does not come naturally to me. How do I change to using nano or vim?
I've tried
export EDITOR=nano
but it doesn't seem to be respected. I'd like visudo to respect this as well.
9
votes
4answers
199 views
+100
Why do I have to re-set env vars in tmux when I re-attach?
I mainly work on a mac and ssh/tmux attach to a Linux machine to do my work. I have ssh-agent running on the Linux machine. I have
set -g update-environment "SSH_AUTH_SOCK SSH_ASKPASS WINDOWID ...
9
votes
1answer
228 views
How do you set up the environment for es?
I've been playing with es the last couple of days, and it (like rc) has the quirk/feature that it only runs its startup script (.esrc) on login. The usual way to run code in each interactive session ...
8
votes
2answers
1k views
What is the significance of single and double quotes in environment variables?
I defined some environment variables in my .profile like this:
MY_HOME="/home/my_user"
but the variable does not seem to evaluate unless I strip off the quotes and re-source the file. I believe ...
8
votes
2answers
367 views
How to run a program in a clean environment in bash?
I want to run a program in an empty environment (i.e. with no envariables set). How to do this in bash?
8
votes
2answers
2k views
In zsh how can I list all the environment variables?
I want to get a list of all environment variables (shell variables? exported variables?) and their values at a given time, in zsh.
What is the proper way to do this?
8
votes
2answers
1k views
What is the difference between ~/.profile, ~/.bashrc, ~/.bash_profile, ~/.gnomerc, /etc/bash_bashrc, /etc/screenrc …?
Answers to the questions on SO and askubuntu, along with poking through (and reading headers of) $HOME and /etc/, indicate a number of files that can be used to set environment variables, including:
...
8
votes
1answer
1k views
What's the difference between “export” and “setenv”?
What's the difference between export and setenv?
8
votes
2answers
173 views
best way to set up separate linux environment in ~
I do most of my work (involves a lot of C/Python) on a development server that is shared with several other people. As a result we all seem to do a bit of the system administration chores (there is ...
7
votes
2answers
248 views
Interactive shell with environment identical to cron
I am aware of a lot of pitfalls in the magic world of crontabs, but sometimes it would help troubleshooting a lot when you have some smart way to enter an interactive (bash) shell with exact identical ...
7
votes
1answer
174 views
How set environment variable based on whether a GUI is available?
How can I set up my .bashrc such that the value of an environment variable changes based on whether or not the current session has access to the gui / windowing system?
For example, let's say I have ...
7
votes
2answers
299 views
How can I create a clean shell environment for temporary use?
I am a frequent answerer on a Unix-focused popular Q&A site, and in many of my answers I provide examples using the bash shell. However, each time I do this I have to manually go through the ...
7
votes
3answers
10k views
How can I run a cron command with existing environmental variables?
How can I run a cron command with existing environmental variables?
If I am at a shell prompt I can type echo $ORACLE_HOME and get a path. This is one of my environmental variables that gets set in ...
6
votes
2answers
269 views
Set the language for a single program execution
Complete C++ i18n gettext() “hello world” example. sets the LANG environment variable using export before executing the program (Linux):
export LANG=es_MX.utf8
./hellogt
Is there a way to set the ...
6
votes
5answers
308 views
PATH environment variable in linux
I want to know how the standard environment variables given by the linux OS like PATH, HOME are set automatically. In which file are these read from. There should be some file from which these ...
6
votes
2answers
969 views
How do you make RPROMPT in zsh update itself on every enter?
My RPROMPT is set to display svn info using vcs_info. It reads RPROMPT=${vcs_info_msg_0_}. vcs_info is called using precmd(). However, RPROMPT doesn't update when I change directories. It works only ...
6
votes
1answer
2k views
How to reset a shell environment?
This issue has been bugging me for a while, and although I've taught I've found my answer through EnvWatcher, unfortunately it only works on Bash. And I use zsh.
I would like to replicate the things ...
6
votes
2answers
1k views
Correctly setting environment
I'm using zsh and gdm to run gnome. Some time ago I discovered that variables are not set correctly. For example LANG/LC_ALL are incorrect ("" instead of en_GB.UTF-8).
I split the .zshrc into .zshrc ...
6
votes
1answer
570 views
Where have I set my bash PATH?
I want to remove ~/bin from my PATH. I set it up months ago when Linux (Ubuntu) was very new to me, but I don't know how I added it...
Nothing shows up when I search all the files listed below.
...
6
votes
4answers
3k views
What environment do I get with sudo?
When I run sudo, what exactly happens to my environment?
When I run sudo command, it doesn't seem to see my or root's environment. For example, my path for both includes /usr/local/bin, but if I try ...
6
votes
2answers
146 views
What does the Enlightenment desktop (E17) environment variable “PANTS=ON” do?
Installing the Enlightenment Window Manager (E17), results in an environment variable being set:
PANTS=ON
What does this environment variable do? What will happen if I set
PANTS=OFF
6
votes
1answer
154 views
Bash executes a different file from the one prompted, even when providing full path
I imagine there's a environment variable or some setting I'm unaware of, but this is driving me nuts.
baco:~ # ls -la /root/subversion-1.4.6/subversion/svnadmin/.libs/svnadmin
-rwxr-x--- 1 ...
5
votes
4answers
2k views
Adding paths to PATH using a multi-line syntax
As far as I understand, the usual way to add a path to the PATH environment variable is by concatenating paths separated by the : character.
For example, if I want to add three paths to it ...
5
votes
4answers
7k views
Export an env variable to be available at all sub shells, and possible to be modified?
Suppose I have
export MY_VAR=0
in ~/.bashrc.
I have an opened gnome terminal, and in this terminal, I change $MY_VAR value to 200. So, if I do
echo $MY_VAR
in this terminal, 200 is shown.
Now, ...
5
votes
2answers
2k views
set LC_* but not LC_ALL
I'd like to have a German (Austria) locale (A4 paper size, 24 hour time, yyyy-mm-dd), but an English-language user interface (I don't like poor translations). I figured that the correct way to achieve ...
5
votes
2answers
349 views
Isn't $HOME supposed to be the location of the user's home directory?
I'm having trouble with a web application I'm writing: The web application, which runs as user nobody, needs to launch an inkscape process to manipulate some SVG files. Because this runs as user ...
5
votes
1answer
464 views
change environment of a running process
How might it be possible to alter some variable in the env of an already running process, for example through /proc/PID/environ? That "file" is read-only.
Need to change or unset the DISPLAY variable ...
5
votes
3answers
2k views
How to read environment variables of a process
Linux's /proc/<pid>/environ does not update (as I understand it, the file contain the initial environment of the process).
How can I read a process's current environment?
5
votes
2answers
236 views
Run a script automatically as I switch to a directory [duplicate]
Possible Duplicate:
Execute bash scripts on entering a directory
I am running an environment which requires some very specific tool versions.
The commands to set up the environment are in a ...
5
votes
1answer
495 views
How can I make variables “exported” in a bash script stick around?
I have multiple Amazon EC2 accounts and want to quickly be able to switch variables, such as $EC2_HOME, using a script.
I have have a shell script set up like this:
#!/bin/sh
export ...
5
votes
1answer
90 views
grep: Ignoring GREP_OPTIONS to search case-sensitive
I have set GREP_OPTIONS="--ignore-case --color" in ~/.bashrc as I normally want grep to work case-insensitive. However, there are times when I need grep to actually search case-sensitive, but the man ...
5
votes
1answer
272 views
Difference between environment variable and shell variable
It is said that environment variables are inherited in child processes but shell variables are not. However the following test shows shell variables are seen in child process just as environment ...
5
votes
4answers
2k views
Run script in a non interactive shell?
I have a cron job that is running a script. When I run the script via an interactive shell (ssh'ed to bash) it works fine. When the script runs by itself via cron it fails.
My guess is that it is ...
5
votes
3answers
230 views
For a same unix or linux user, different sets of environment variables
I'm using tcsh, and for a specific project every member of my team connects to a server with the same user. (This is something we cannot change).
The situation arises because I want to have some ...
5
votes
1answer
880 views
using environment variables in tmux.conf files
Is it possible to use an environment variable in a tmux.conf file? I am trying to set a default-path to an environment variable. Currently what I am trying is:
set -g default-path $MYVAR
further I ...
5
votes
2answers
324 views
Prevent SSH client passing TERM environment variable to server?
I'm currently using Fedora 18 gnome-terminal, then started tmux multiplexer in it. After I connected to a CentOS 5 server via ssh command, I find:
ls result has no color
tmux, screen, hexedit, htop ...
4
votes
3answers
259 views
Need help deciphering unix statement
I need help deciphering what is being said here:
export IP=`/sbin/ifconfig | grep 'inet addr:'|grep -v '127.0.0.1'|
cut -d: -f2 | awk '{print $1}'`
I know it is to set IP as an environment ...
