Tagged Questions
82
votes
4answers
135k 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 ...
35
votes
4answers
3k 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...
34
votes
4answers
1k views
What exactly is an environment variable?
I know that VARIABLE=value creates an environment variable, and export VARIABLE=value makes it available to processes created by the current shell. env shows the current environment variables, but ...
20
votes
5answers
710 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 ...
19
votes
2answers
7k 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:
...
18
votes
6answers
6k views
How to print only defined variables (shell and/or environment variables) in bash
The bash builtin command set, if invoked without arguments, will print all shell and environment variables, but also all defined functions. This makes the output unusable for humans and difficult to ...
17
votes
5answers
956 views
why is setting a variable before a command legal in bash?
I've just encountered several answers such as to parsing a delimited text file... that use the construct:
while IFS=, read xx yy zz;do
echo $xx $yy $zz
done < input_file
where the IFS ...
13
votes
3answers
3k 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?
12
votes
2answers
328 views
How do I start all shell sessions in a directory other than $HOME?
When I open my non-login shell in Ubuntu, my present working directory is /home/user_name (my $HOME environment variable), but I want to change this such that when I start my terminal I am in some ...
10
votes
4answers
7k 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?
10
votes
3answers
224 views
Using variables to store terminal color codes for PS1?
In my .bashrc, I use ANSI terminal color codes to colorize various bits. It looks like this:
PS1='\u@\h:\w\[\033[33m\]$(virtual_env)\[\033[32m\]$(git_branch)\[\033[0m\]$ '
where virtual_env and ...
10
votes
2answers
994 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 ...
8
votes
2answers
398 views
using export in .bashrc
I have noticed in my .bashrc, that some lines have export in front, such as
export HISTTIMEFORMAT="%b-%d %H:%M "
...
export MYSQL_HISTFILE="/root/.mysql_history"
whereas other have not, such as
...
8
votes
4answers
85 views
Save output of command that modifies environment into a variable
How to save output of a command that modifies environment into a variable?
I'm using bash shell.
Assume that I have:
function f () { a=3; b=4 ; echo "`date`: $a $b"; }
And now, I can use commands ...
8
votes
1answer
969 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.
...
7
votes
1answer
2k 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 ...
6
votes
2answers
7k views
How to alter PATH within bash script?
I have several projects that require me to change versions of Java/Grails/Maven. I'm trying to handle this with some Bash scripts that would make the changes. For example:
#!/bin/sh
export ...
6
votes
2answers
437 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
4answers
15k 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
13k views
Refresh env variables after editing bashrc file
I frequently edited the .bashrc file to export new environment variables.
Rather than close the console and start a new one to refresh the env variables, is there a convenient way to refresh?
5
votes
2answers
161 views
if statement in .bashrc not working correctly
I set up .bashrc to show a long prompt if the terminal is at least 80 characters wide. Otherwise it shows a degraded, smaller prompt.
I use an if statement to achieve this:
dp_smaller_than=80
if [ ...
5
votes
2answers
3k views
Set Variable Environment Variables in bash (or other)
I want my script to read a file containing key/value pairs of environment variables to set, and then to set them.
So far, I have this:
#!/bin/bash
cat $1 | while read kv
do
key=${kv%=*}
...
5
votes
4answers
1k views
Last failed command in bash
The $? variable holds the exit status of last run command. Is there a variable that holds last run command itself?
5
votes
1answer
628 views
Difference between environment variable and shell variable
It is said that environment variables are inherited in child processes but shell variables are not. However the following test shows shell variables are seen in child process just as environment ...
5
votes
3answers
312 views
Is there any harm in using variables that aren't set?
Say I have the following code:
# Check if the color prompt is enabled and supported on this system
if [ -n "$force_color_prompt" ] && [ -x /usr/bin/tput ] && tput setaf 1 ...
4
votes
4answers
1k views
What is the `editor` command in bash?
I was looking for a command that would hopefully open the current user's favourite text editor, because I am writing out some instructions with commands in a blog. I was expecting a command like edit, ...
4
votes
2answers
81 views
how to prevent exported environment variables to be recognized/accessible by a child shell (bash)?
So, I need to prevent loads of exported variables to be recognized by a child shell.
The problem is an application (Wine+UDK) wont build projects with too many (>65535) bytes on the environment, ...
4
votes
4answers
585 views
Detecting X session in a bash script (.bashrc etc.)
Recently I put xset b off to my .bashrc. Now I'm annoyed by the error thet pops up when I log in via tty or via ssh, i.e. outside X session.
First thing that came in my mind was [[ -z "$SOME_VAR" ]] ...
4
votes
3answers
94 views
Why does export -p exclude $_ variable?
As far I know, there are 3 ways to see exported variables:
$ export -p | wc -l
50
$ env | wc -l
51
$ printenv | wc -l
51
As you can see, export -p misses single variable. It's a $_ one:
$ diff ...
4
votes
3answers
1k views
Bash shells with different environment variables
I want to somehow enter a different bash shell with some altered environment variables.
For example, if I run script bfin.sh and it contains something like
export PATH=/home/me/bfin2012:$PATH
I ...
4
votes
2answers
146 views
Why do newlines mess up my while condition?
I have a while loop that allows setting variables when written one way but does not allow it when written another way. Why is that? This prints var as 1234 and does not print var2
#!/bin/bash
...
4
votes
1answer
3k views
dot file not sourced when running a command via ssh
When I run my program interactively, it works fine:
ssh somehost
$ ~/some/path/somescript.py
When I run my program over ssh directly, it doesn't work. The variable PYTHONPATH is not set, because ...
4
votes
2answers
301 views
Inhibit Variable Expansion in Paths
How do I prevent Zshell (and Bash I assume) from expanding environment variables in paths be completed as shown in the following example:
$PREFIX/alt/li
should expand to
$PREFIX/alt/lib
and not ...
3
votes
1answer
78 views
Difference between “.” and “./” while setting the environment variables using export? [duplicate]
Please excuse me if I am not clear while asking questions. I will try my best to be very clear while asking questions.
While learning Embedded Linux, we are setting an environment for our project. ...
3
votes
3answers
297 views
Adding prefixes/suffixes to file names without typing it all over again?
I would like to do something like the following
$ tmp=name*
$ mv $tmp new_$tmp
$ ls new_*
$ new_name-with-stuff-i-dont-want-to-type name-with-stuff-i-dont-want-to-type
Setting the environment ...
3
votes
2answers
771 views
Environment variable set but not respected
I find the following behavior a little confusing, can someone please explain why it happens?
In /etc/bash.bashrc I have:
EDITOR=vim
And it is indeed set:
lev@home ~ $ echo $EDITOR
vim
I would ...
3
votes
3answers
99 views
Environment variables are not set when my function is called in a pipeline
I have the following recursive function to set environment variables:
function par_set {
PAR=$1
VAL=$2
if [ "" != "$1" ]
then
export ${PAR}=${VAL}
echo ${PAR}=${VAL}
shift
...
3
votes
3answers
478 views
How do I create a GUI application launcher for xfce4-terminal with fish but inheriting the environment variables from bash?
If I run fish from a bash prompt, it will inherit the environment variables I have set in my .bashrc and .profile files, including the important $PATH variable. So far so good.
Now, I want ...
3
votes
1answer
35 views
How to read value of variable, where the name of variable is the value of another variable
I think an example is in order. Consider I have these two environment variables setup (by a Continuous Delivery tool): PACKAGE_VER=1.2.3 and USE_VERSION_FROM=PACKAGE_VER.
What I want now is a script ...
3
votes
1answer
210 views
How to print apparently hidden environment variables?
Environment variables can be shown with env; but, some are not shown. For example...
echo $EUID might produce as result of 1000 yet
env | grep EUID produces no result.
What is this type of variable? ...
3
votes
6answers
3k views
ssh user@IP sh <command> missed environment variables
I use an approach
ssh user@IP sh [runme.sh]
to execute script remotely, this works fine. But I got one problem, that is in runme.sh, I can't get any envirnoment variables which are defined in ...
3
votes
2answers
66 views
Messed up bash.bashrc file, commands not working anymore
Trying installing Java, I tried to add it to the executable path with the line:
export PATH=/usr/lib/jvm/jdk1.7.0_60/bin:$PATH
in the system-wide /etc/bash.bashrc file.
For some reason this ...
3
votes
0answers
116 views
tab-expansion and “./” bash shell [closed]
Maybe someone here would be able to help me out. Have installed Ubuntu 12.04 LTS (kubuntu) on two machines. The .bashrc and .bash_profile files are identical as the file structures on each machine is ...
2
votes
1answer
158 views
Why does this variable have no value even though it is set in .bashrc?
If I append this:
hi=11
export hi
to the .bashrc and then I su to this user with:
su - bela
then I:
echo $hi
11
Then it's working, the "hi" variable has the value of "11". But. When I:
...
2
votes
4answers
303 views
bash script and local env variable namespace collision
I have a bash script with a variable called VAR_A
I also have a local env variable called VAR_A
The bash script calls the command:
echo ${VAR_A}
I am not able to change the variable in the script ...
2
votes
2answers
76 views
What does `env COLUMNS=%S ps …` do?
I have seen the syntax env COLUMNS=%sin shell scripts, e.g. see the line below from the Helm package in Emacs:
env COLUMNS=%s ps -axo pid,user,pri,nice,ucomm,tty,start,vsz,%%cpu,%%mem,etime,command
...
2
votes
2answers
5k views
Multiple path environment variable setup lines with bash
I have very long export PATH=A:B:C .... Can I make a multiple lines to have more organized one as follows?
export PATH = A:
B:
C:
2
votes
2answers
335 views
Function to evaluate variables in BASH
Given a variable name is there a function that will print its value?
Often times I pass the name of a variable to a bash function and instead of doing the expansion while passing it I would like to ...
2
votes
4answers
109 views
How do I pass a variable from my local server to a remote server?
I am trying to pass a variable from my local server (location1) to a remote server (location2). The purpose of the code is to copy a file from the remote server from a predefined location. In simpler ...
2
votes
1answer
7k views
bash setenv command is not found
every body I am new in centos server I am getting a error while using following command
setenv CLASSPATH /path/mysql-connector-java-ver-bin.jar:$CLASSPATH
error is
bash setenv ...
