Using a **Linux shell**, how do I start a program with a different working directory from the current working directory?

For example, I have a binary file `helloworld` that creates the file `hello-world.txt` in the **current directory**. 
&lt;br&gt;&lt;br&gt;
This file is inside of directory `/a`. 

Currently, I am in the directory `/b`. I want to start my program running `../a/helloworld` and get the `hello-world.txt` somewhere in a third directory `/c`.

How do I run a program with a different working directory from current, from Linux shell?

How is it possible to change the default shell? The `env` command currently says:

    SHELL=/bin/tcsh

and I want to change that to Bash.


Changing default shell in Linux

conda 4.2.13
MacOSX 10.12.1

I am trying to install packages from `pip` to a fresh environment (virtual) created using anaconda.  [In the Anaconda docs][1] it says this is perfectly fine.  It is done the same way as for virtualenv.  

&gt; Activate the environment where you want to put the program, then pip install a program...

I created an empty environment in Ananconda like this:

    conda create -n shrink_venv

Activate it:

    source activate shrink_venv

I then can see in the terminal that I am working in my env `(shrink_venv)`.  Problem is coming up, when I try to install a package using `pip`:

    (shrink_venv): pip install Pillow

    Requirement already satisfied (use --upgrade to upgrade): Pillow in /Library/Python/2.7/site-packages

So I can see it thinks the requirement is satisfied from the system-wide package.  So it seems the environment is not working correctly, definitely not like it said in the docs.  Am I doing something wrong here?

Just a note, I know you can use `conda install` for the packages, but I have had an issue with Pillow from anaconda, so I wanted to get it from `pip`, and since the docs say that is fine.

Output of `which -a pip`:

    /usr/local/bin/pip
    /Users/my_user/anaconda/bin/pip

** UPDATE **
I see this is pretty common issue. What I have found is that the conda env doesn&#39;t play well with the PYTHONPATH. The system seems to always look in the PYTHONPATH locations even when you&#39;re using a conda environment. Now, I always run `unset PYTHONPATH` when using a conda environment, and it works much better. I&#39;m on a mac.

  [1]: http://conda.pydata.org/docs/using/pkgs.html#install-non-conda-packages

Using Pip to install packages to Anaconda Environment

What&#39;s the difference between system properties [System.getProperties()][1] and environment variables [System.getenv()][2] in a JVM?


  [1]: http://download.oracle.com/javase/6/docs/api/java/lang/System.html#getProperties%28%29
  [2]: http://download.oracle.com/javase/6/docs/api/java/lang/System.html#getenv%28%29

Java system properties and environment variables

Is it possible to change current directory from a script?

I want to create a utility for directory navigation in Bash. I have created a test script that looks like the following:

    #!/bin/bash
    cd /home/artemb

When I execute the script from the Bash shell the current directory doesn&#39;t change. Is it possible at all to change the current shell directory from a script?

Change the current directory from a Bash script

What is the best (or as good as possible) general SVN ignore pattern to use? 

There are a number of different IDE, editor, compiler, plug-in, platform, etc. specific files and some file types that &quot;overlap&quot; (i.e. desirable for some types projects and not for others). 

**There are however, a large number of file types that you just never want included in source control automatically regardless the specifics of your development environment.**

The answer to this question would serve as a good starting point for any project - only requiring them to add the few environment specific items they need. It could be adapted for other Version Control Systems (VCS) as well.

Best general SVN Ignore Pattern?

On Linux, I can do:

    $ FOO=BAR ./myscript

to call &quot;myscript&quot; with the environment variable FOO being set.

Is something similar possible in PowerShell, i.e. without having to first set the variable, call the command, and then unset the variable again?

To be more clear about my use case - I don&#39;t want to use this as part of a script. Rather, I have a third-party script whose behavior I can control using environment variables, but, in this case, not command line arguments. So being able to alternate between typing

    $ OPTION=1 ./myscript

and

    $ ./myscript

would just be very handy.


PowerShell: Setting an environment variable for a single command only

Is it possible to get the name of the currently logged in user (Windows/Unix) and the hostname of the machine?

I assume it&#39;s just a property of some static environment class.

I&#39;ve found this for the user name

    com.sun.security.auth.module.NTSystem NTSystem = new
            com.sun.security.auth.module.NTSystem();
    System.out.println(NTSystem.getName());

and this for the machine name:

    import java.net.InetAddress;
    ...
    String computerName;
    ...
    try {
        computerName = InetAddress.getLocalHost().getHostName();
    }
    
    catch(Exception ex) {
        ...
    }

Is the first one just for Windows?

And what will the second one do, if you don&#39;t have a hostname set?


Java current machine name and logged in user?

I&#39;m writing a rake task that does some DB work outside of Rails/ActiveRecord.

Is there a way to get the DB connection info (host, username, password, DB name) for the current environment as defined in `database.yml`?

I&#39;d like to get it so I can use it to connect like this...

    con = Mysql.real_connect(&quot;host&quot;, &quot;user&quot;, &quot;pw&quot;, &quot;current_db&quot;)

Can you get DB username, pw, database name in Rails?

In Windows environment there is an API to obtain the path which is running a process. Is there something similar in Unix / Linux?

Or is there some other way to do that in these environments?


How do I get the path of a process in Unix / Linux

&gt; **Possible Duplicate:**
&gt; [What&amp;#39;s the difference between .bashrc, .bash_profile, and .environment?](https://stackoverflow.com/questions/415403/whats-the-difference-between-bashrc-bash-profile-and-environment)

&lt;!-- End of automatically inserted text --&gt;

It seems that if I use

    alias ls=&#39;ls -F&#39;

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:

&gt; For non-login shell

and the `.bash_profile` file has a comment that says

&gt; 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&#39;t work on Mac OS X, it seems.


About .bash_profile, .bashrc, and where should alias be written in?

I need to create one config option for my Rails application. It can be the same for all environments. I found that if I set it in `environment.rb`, it&#39;s available in my views, which is exactly what I want...

    environment.rb

    AUDIOCAST_URI_FORMAT = http://blablalba/blabbitybla/yadda

Works great.

However, I&#39;m a little uneasy. Is this a good way to do it? Is there a way that&#39;s more hip?

Best way to create custom config options for my Rails app?

I&#39;ve used a number of different *nix-based systems of the years, and it seems like every flavor of Bash I use has a different algorithm for deciding which startup scripts to run.  For the purposes of tasks like setting up environment variables and aliases and printing startup messages (e.g. MOTDs), which startup script is the appropriate place to do these?

What&#39;s the difference between putting things in `.bashrc`, `.bash_profile`, and `.environment`?  I&#39;ve also seen other files such as `.login`, `.bash_login`, and `.profile`; are these ever relevant?  What are the differences in which ones get run when logging in physically, logging in remotely via ssh, and opening a new terminal window?  Are there any significant differences across platforms (including Mac OS X (and its Terminal.app) and Cygwin Bash)?

What&#39;s the difference between .bashrc, .bash_profile, and .environment?

I&#39;ve tried various forms of the following in a bash script:

    #!/bin/bash
    svn diff $@ --diff-cmd /usr/bin/diff -x &quot;-y -w -p -W $COLUMNS&quot;
But I can&#39;t get the syntax to correctly expand the `COLUMNS` environment variable.

I&#39;ve tried various forms of the following:

    svn diff $@ --diff-cmd /usr/bin/diff -x &#39;-y -w -p -W $COLUMNS&#39;
and

    svn diff $@ --diff-cmd /usr/bin/diff -x &#39;-y -w -p -W ${COLUMNS}&#39;
and

    eval svn diff $@ --diff-cmd /usr/bin/diff -x &quot;-y -w -p -W $COLUMNS&quot;

Suggestions?

How to use an environment variable inside a quoted string in Bash

Using this:

    Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData)

I get this output:

    &quot;C:\\Documents and Settings\\[USER]\\Application Data&quot;

How can I get the root directory of all users? i.e.:

    &quot;C:\\Documents and Settings\\[USER]\\&quot;

How can I get the current user directory?

It would be helpful if someone can illustrate this with a simple example?

Also, where would it be useful to use `parent.frame()` instead of `parent.env()` and vice versa.



What is the difference between parent.frame() and parent.env() in R; how do they differ in call by reference?

When I run:
C:\Users\ashahria\Downloads&gt;java -jar schemaSpy_5.0.0.jar

I get the error below. What is wrong? How can I fix it?

&gt;Error: Registry key &#39;Software\JavaSoft\Java Runtime Environment&#39;\CurrentVersion&#39;
&gt;
&gt;has value &#39;1.5&#39;, but &#39;1.7&#39; is required.&lt;br/&gt;
&gt;Error: could not find java.dll&lt;br/&gt;
&gt;Error: Could not find Java SE Runtime Environment.

Error: Registry key &#39;Software\JavaSoft\Java Runtime Environment&#39;\CurrentVersion&#39;?

I have some code that needs to run only if the rails app is in the development environment (i.e. $ rails server) but not in the test environment (i.e. $ rake test).

When I try

    if Rails.env.development?
        dont run me during testing
    end

the code gets executed regardless of which environment I am in. I&#39;ve even tried:

    if Rails.env.development? and not Rails.env.test?
        NO, REALLY, DONT RUN ME DURING TESTING
    end

but no love.

What should I be doing instead?



How can I determine if my rails is in the development environment and not the test environment?

I&#39;m looking for something like `git list-path` printing the
path of the associated repository (the `.git` directory).

A bit of background: I have set up git version control on quite a few of my
projects/folders.  Some of them are nested, so one directory with echo own repository is a subfolder to another directory tracked with another repository. 

 E.g. in my home directory (`~`) I use git to track my dot files, but
in folder `~/photo/meta-mix/` I have another project I track with a
separate repository. Now, say,I have set up another project in directory
`~/photo/meta-match/`, but I don&#39;t know anymore whether it has its own
repository. So I want to find out whether this directory is version
controlled and where its repository is.

How can I do this with a git command? `git status` can give me 

    nothing to commit

in *both* cases, when `~/photo/meta-match/` has its own repository or when it just refers to the repository of `~`. 

How to find the path of the local git repository when I am possibly in a subdirectory

Suppose there&#39;s an executable and a Python script to launch it, and they&#39;re located in &#39;sibling&#39; subdirectories, e.g.

    /tmp/subdir1/myexecutable
    /tmp/subdir2/myscript.py

If in `/tmp` and running `python subdir2/myscript.py` with a relative path to executable

    # myscript.py
    from subprocess import Popen
    proc = Popen([&quot;../subdir1/myexecutable&quot;])

It makes `OSError: [Errno 2] No such file or directory`.

How does the Python search for the executable? Does it use the current working directory and/or location of the script? Does it use PATH and/or PYTHONPATH? Can you change where and how `subprocess.Popen` searches for the executable? Are commands, absolute and relative paths for executables treated differently? Are there differences between Linux and Windows? What does `shell=True` or `shell=False` influence?


python subprocess Popen environment PATH?

I was looking for a way to set the environment path variable with a .cmd file.  
When the path variable was getting too long, I got some errors.  
Just add the needed variables to &#39;Set Path variable&#39; below  
Check the current value of your path variable and add to the script  
**Run the script as administrator!**  
Open a new console window and it should work e.g. php -v



Set windows environment variables with a batch file

I used to use the shebang 

    #!/usr/bin/env python

When is it better to use

    #!/usr/bin/python

What is the exact difference between them?

What&#39;s the difference between python shebangs with /usr/bin/env rather than hard-path?

Can some one explain what it means in simple terms. Does it mean the environment (DOS, Windows, Linux, etc) where the application codes are run?

What is run time environment?

I am able to run a sample hadoop program from the command prompt and am trying to run the same program from Eclipse, so that I can debug it and understand it better.

For the command line program, some environment variables are set in the `.bashrc` and the same are being read as `System.getenv().get(&quot;HADOOP_MAPRED_HOME&quot;)` in the hadoop program. But, when I am running a java program with `System.getenv().get(&quot;HADOOP_MAPRED_HOME&quot;)`, from Eclipse I am getting null.

I tried passing `-DHADOOP_MAPRED_HOME=test` to VM parameters in the runtime configurations from Eclipse, but still getting null in the standalone program. How to make the environment variables visible within Eclipse? When I iterate through `System.getenv()` in Eclipse, I see lot of variables like `DISPLAY`, `USER`, `HOME` and others. Where are they set? I am using Ubuntu 11.04.

Environment variables in Eclipse

I am using seed.rb to populate both my development and production database. I usually populate the first with dummy data and the latter with the real minimal data that my app needs to run (e.g. the first user and so on).

How can I specify in seed.rb for what environment each data is?

Given that I know &quot;group&quot; to be a Gemfile method, I&#39;d like to achieve the same behavior for seed.rb.

E.g. I&#39;d like to write something like this in my seed.rb:

    group :development do 
      # development specific seeding code
    end

    group :production do 
      # production specific seeding code
    end

    # non-specific seeding code (it always runs) 

This to be able to call both the development-specific and the non-specific code with

    $ rake db:seed

And to call both the production-specific and the non-specific code with:

    $ rake db:seed RAILS_ENV=production 


Thank you

How to use seed.rb to selectively populate development and/or production databases?

I want to know how to create a simple desktop environment, such as KDE, Gnome and LXDE, for Linux, or specifically, Ubuntu/Kubuntu, but I do not know how to begin and how complex it is.

I want to create a simple, efficient and lightweight desktop and to reproduce some good features from KDE, Gnome and Windows XP. I do not want to reinvent the wheel, I want to design the graphical interface and main dialogs.

I could use C++ with Qt, or maybe with X11 calls. A simple desktop like TWM would be the first step, then I could add taskbar, start menu, new features and play with new ideas.

Thanks.


**Edit**

I have installed icewm and I think it is what I need to begin. On the login screen, I can choose if I use KDE (desktop environment) or icewm (window manager). I do not understand what a window manager actually is.

I have downloaded icewm source code and I am confused. There are some concepts that I have to understand, such as, what happens after the login screen when the desktop is loaded, how a window works, etc.


**Edit 2**

I think I need a good tutorial. I have to understand how a Window Manager or Desktop Environment work. There are some concepts that I have to know.


How to create a simple desktop environment?

I have a ridiculous question due to a ridiculous problem. 

Normally if I want to get the contents of an environment variable in UNIX shell, I can do

    echo ${VAR}

Let&#39;s assume, due to my ridiculous situation, that this isn&#39;t possible. 

How do I get the contents of an environment variable to stdout, without someone who is looking at the command itself (not the output), see the value of the environment variable.

I can picture the solution being something like `echo env(NAME_OF_VAR)` although I can&#39;t seem to find it. The solution has to work in sh.

PS I can&#39;t write a script for this, it must be a built in unix command (i know, ridiculous problem)

Thanks (and sorry for the absurdity)


UNIX, get environment variable

I have an issue with connecting environment to my Spring project.
In this class 

    @Configuration
    @ComponentScan(basePackages = &quot;my.pack.offer.*&quot;)
    @PropertySource(&quot;classpath:OfferService.properties&quot;)
    public class PropertiesUtil {
        @Autowired
        private Environment environment;

       

        @Bean
        public String load(String propertyName)
        {
            return environment.getRequiredProperty(propertyName);
        }
    }

environment always is null. 




Autowired Environment is null

I want to add a conda channel to a specific [conda environment](http://conda.pydata.org/docs/using/envs.html) but when I use 

    conda config --add channels glotzer

that channel is now available from all my conda environments.  In addition to testing an install from another environment, the `~/.condarc` file has the following:

    channels:
      - glotzer
      - defaults

How would I configure conda so the channel is only available from a specific environment?

I did find in the [channel documentation](http://conda.pydata.org/docs/channels.html) that for conda &gt;= 4.1.0, putting channels at the bottom of the `~/.condarc` will prevent added channels from overiding the core package set.

&gt; By default conda now prefers packages from a higher priority channel over any version from a lower priority channel. Therefore you can now safely put channels at the bottom of your
&gt; channel list to provide additional packages that are not in the
&gt; default channels, and still be confident that these channels will not
&gt; override the core package set.

I expect this will prevent most problems, except when in one environment you do want the package added through a channel to override a core package.

All Environment Solutions on Gang of Coders

Total of 29 Environment Solutions