I am not sure if thats what you want, but try `printenv`  
This will show you all your environment variables.  

About where they are stored  
https://stackoverflow.com/questions/532155/linux-where-are-environment-variables-stored

How to set Shell Environment Variables  
http://www.codecoffee.com/tipsforlinux/articles/030.html

Happy reading :-)


Just execute `env` in a terminal.

Example output:

    $ env
    TERM=xterm
    SHELL=/bin/bash
    USER=joksnet
    USERNAME=joksnet
    DESKTOP_SESSION=gnome
    PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games
    PWD=/home/joksnet
    GDM_KEYBOARD_LAYOUT=us
    LANG=en_US.utf8
    HOME=/home/joksnet
    DISPLAY=:0.0
    COLORTERM=gnome-terminal
    _=/usr/bin/env

Or **set**:

    SET(P)                                                                  POSIX Programmer’s Manual                                                                  SET(P)
    
    NAME
           set - set or unset options and positional parameters
    
    SYNOPSIS
           set [-abCefmnuvx][-h][-o option][argument...]
    
           set [+abCefmnuvx][+h][+o option][argument...]
    
           set -- [argument...]
    
           set -o
    
           set +o
    
    DESCRIPTION
           If  no  options or arguments are specified, set shall write the names and values of all shell variables in the collation sequence of the current locale. Each name
           shall start on a separate line, using the format:
    
                  &quot;%s=%s\n&quot;, &lt;name&gt;, &lt;value&gt;
    
           The value string shall be written with appropriate quoting; see the description of shell quoting in Quoting . The output shall be  suitable  for  reinput  to  the
           shell, setting or resetting, as far as possible, the variables that are currently set; read-only variables cannot be reset.

I am using [Paperclip][1] (w/ Amazon s3) on Rails 3. I want to delete an existing attachment **without replacing it** using an update action.

I&#39;ve only found one example of this [here][2] and could not get that to work, it just wouldn&#39;t delete and there was nothing in the logs to say why. I wanted to do something like this on the form:

    &lt;%- unless @page.new_record? || !@page.image? -%&gt;
        &lt;%= f.check_box :image_delete, :label =&gt; &#39;Delete Image&#39; %&gt;
    &lt;%- end -%&gt;

(page is the name of the model, image is the attribute name which holds the attachment)

But how do I detect that checkbox and more importantly, how do I delete the image? I appreciate any help!

  [1]: https://github.com/thoughtbot/paperclip
  [2]: http://thewebfellas.com/blog/2008/11/2/goodbye-attachment_fu-hello-paperclip

Rails Paperclip how to delete attachment?

I have a string `s`, its contents are variable. I&#39;d like to make it a raw string. How do I go about this? 

Something similar to the `r&#39;&#39;` method.


Convert regular Python string to raw string

I would like to find out my environment variables in bash. Are they stored somewhere?

What are my environment variables?

<p>I would like to find out my environment variables in bash. Are they stored somewhere?</p>


I want to create an alias in `bash` like this: 

    alias tail_ls=&quot;ls -l $1 | tail&quot;

Thus, if somebody types:

    tail_ls /etc/ 

it will only show the last 10 files in the directory.

But `$1` does not seem to work for me. Is there any way I can introduce variables in bash.


Alias with variable in bash

How do I extract the list of supported Unicode characters from a TrueType or embedded OpenType font on Linux?

Is there a tool or a library I can use to process a .ttf or a .eot file and build a list of code points (like U+0123, U+1234, etc.) provided by the font?

Finding out what characters a given font supports

I am trying to use `grep` to match lines that contain two different strings. I have tried the following but this matches lines that contain either *string1* **or** *string2* which not what I want.

    grep &#39;string1\|string2&#39; filename


So how do I match with `grep` only the lines that contain *both strings*?

Match two strings in one line with grep

I have many files with .txt extension.
How to remove .txt extension for multiple files in linux?

I found that

    rename .old .new *.old

substitutes `.old` extension to the `.new`

Also I want to do this for files in sub-folders.

Linux: remove file extensions for multiple files

Is there a way to limit the depth of a recursive file listing in linux?

The command I&#39;m using at the moment is:

    ls -laR &gt; dirlist.txt

But I&#39;ve got about 200 directories and each of them have 10&#39;s of directories. So it&#39;s just going to take far too long and hog too many system resources.

All I&#39;m really interested in is the ownership and permissions information for the first level subdirectories:

    drwxr-xr-x 14 root   root  1234 Dec 22 13:19 /var/www/vhosts/domain1.co.uk  
    drwxr--r-- 14 jon    root  1234 Dec 22 13:19 /var/www/vhosts/domain1.co.uk/htdocs  
    drwxr--r-- 14 jon    root  1234 Dec 22 13:19 /var/www/vhosts/domain1.co.uk/cgi-bin  
    drwxr-xr-x 14 root   root  1234 Dec 22 13:19 /var/www/vhosts/domain2.co.uk  
    drwxr-xrwx 14 proftp root  1234 Dec 22 13:19 /var/www/vhosts/domain2.co.uk/htdocs  
    drwxr-xrwx 14 proftp root  1234 Dec 22 13:19 /var/www/vhosts/domain2.co.uk/cgi-bin  
    drwxr-xr-x 14 root   root  1234 Dec 22 13:19 /var/www/vhosts/domain3.co.uk  
    drwxr-xr-- 14 jon    root  1234 Dec 22 13:19 /var/www/vhosts/domain3.co.uk/htdocs  
    drwxr-xr-- 14 jon    root  1234 Dec 22 13:19 /var/www/vhosts/domain3.co.uk/cgi-bin  
    drwxr-xr-x 14 root   root  1234 Dec 22 13:19 /var/www/vhosts/domain4.co.uk  
    drwxr-xr-- 14 jon    root  1234 Dec 22 13:19 /var/www/vhosts/domain4.co.uk/htdocs
    drwxr-xr-- 14 jon    root  1234 Dec 22 13:19 /var/www/vhosts/domain4.co.uk/cgi-bin

  
  
&lt;b&gt;EDIT:&lt;/b&gt;

Final choice of command:

    find -maxdepth 2 -type d -ls &gt;dirlist

How to limit depth for recursive file list?

&gt; ${parameter:=word}
&gt;               Assign Default Values.  If parameter is unset or null, the
&gt; expansion of word is assigned to
&gt; parameter.  The value of parameter is
&gt; then  substituted.   Positional 
&gt; parameters  and  special
&gt;               parameters may not be assigned to in this way.

   
I thought I could use this feature to write `${LONG_VARIABLE_NAME:=hello}` instead of the longer `LONG_VARIABLE_NAME=${LONG_VARIABLE_NAME:-hello}`, but now bash also tries to execute &#39;hello&#39; and that gives a command not found. Any way to avoid that? Or will I have to stick to the latter? Can someone give an example where the assign default is actually useful?

bash assign default value

What type of parameter/flag can I use with the Unix `find` command so that I search executables?



Search for executable files using find command

I can type alias to show a list of all the aliases.

But for functions, all I can do is grep my `.bash_profile`.

That only gets the ones in that file, not those defined in subsidiary files or dynamically.

Is there a more convenient way to find out what functions are currently defined?

How do I list the functions defined in my shell?

I&#39;ve been using Git on both Windows and Ubuntu during the development of a small project, frequently flipping back and forth between the two. The issue is that *Git Bash* consistently becomes slow.

When I say slow, I mean that running `cd` takes anywhere from 8-25 seconds, running `git` commands take from 5-20 seconds, and `ls` can take up to 30 seconds sometimes. Needless to say, this is not fun, not to mention unproductive. I know Git is slower on Windows, but this is ridiculous.

The one solution which has worked--temporarily--for me has been to disable my network connection (as suggested in [this answer][1]), start Git Bash, and then reconnect. Sometimes it continues to run quickly for days after doing that, but the performance always degrades eventually. I&#39;ve trawled through the msysgit discussion group, Stack&amp;nbsp;Overflow, msysgit issue list, etc. on and off for weeks, but I haven&#39;t been able to turn up solutions which work.

So far, I&#39;ve tried:

 - Adding Git &amp; project folders to the virus scanner&#39;s exclusion list
 - Disabling my virus scanner completely (Kaspersky IS 2011)
 - Ensuring that Outlook is not running (Outlook 2007)
 - Shutting down all other applications
 - Running Git Bash as administrator
 - Disabling network connection, starting Git Bash, and keeping connection disabled
 - Disabling network connection, starting Git Bash, re-enabling connection (works only occasionally)
 - Running `git gc`
 - And combinations of the above

I did read that a couple of people had success disabling Bash completion, but ideally I&#39;d like to keep that active. The version of msysgit is 1.7.3.1-preview20101002 &amp; the OS is Windows 7 x64. Running the same things on Linux is, predictably, lightning fast. I would use Linux exclusively, but I need to run stuff in Windows, too (certain applications, testing, etc.).

Has anyone encountered a similar issue? If so, what was the underlying problem and what was the solution (if any)?

This extends beyond just the Git repositories, but just for reference, the repositories I&#39;ve been using Git with have been pretty small: ~4-50 files maximum.

  [1]: https://stackoverflow.com/questions/2835775/msysgit-bash-is-horrendously-slow-in-windows-7



Git Bash is extremely slow on Windows 7 x64

Is there any way to get the SSID of the current wireless network through a shell script on Mac OS X?

Get wireless SSID through shell script on Mac OS X

Is there a way to get the size of a remote file like

    http://api.twitter.com/1/statuses/public_timeline.json

in shell script?

How to get remote file size from a shell script?

As far as I know, using `&amp;` after the command is for running it in the background.

Example of `&amp;` usage: `tar -czf file.tar.gz dirname &amp;`

But how about `&amp;&amp;`? ([example][1])


  [1]: https://serverfault.com/questions/215179/centos-100-disk-full-how-to-remove-log-files-history-etc#answer-215188

What is the purpose of &quot;&amp;&amp;&quot; in a shell command?

When using a *nix shell (usually bash), I often spawn a sub-shell with which I can take care of a small task (usually in another directory), then exit out of to resume the session of the parent shell.

Once in a while, I&#39;ll lose track of whether I&#39;m running a nested shell, or in my top-level shell, and I&#39;ll accidentally spawn an additional sub-shell or exit out of the top-level shell by mistake.

Is there a simple way to determine whether I&#39;m running in a nested shell?  Or am I going about my problem (by spawning sub-shells) in a completely wrong way?

How do I know if I&#39;m running a nested shell?

I am running the 32bit version of Ubuntu 10.10 and trying to cross compile to a 64 bit target. Based on my research, I have installed the g++-multilib package.

The program is a very simple hello world:

    #include &lt;iostream&gt;
    
    int main( int argc, char** argv )
    {
      std::cout &lt;&lt; &quot;hello world&quot; &lt;&lt; std::endl;
      return 0;
    }

Compile:

    g++ -m64 main.cpp

Error:

    In file included from main.cpp:1:
    /usr/include/c++/4.4/iostream:39: fatal error: bits/c++config.h: No such file or directory
    compilation terminated.

I have found a `c++config.h` file but they reside under the `i486-linux-gnu` and `i686-linux-gnu` directories in `/usr/include/c++/4.4/` There is not `c++config.h` in `/usr/include/c++/bits`.

Any ideas on what I am missing? Compiling without the `-m64` flag works fine (a.out is created and runs correctly).

**Edit** Thanks to the hint from @nightcracker, I did a little more investigation into the include structure on the 32 and 64 bit systems. I have added an [answer][1] below that &quot;fixes&quot; the problem temporarily but I think it will break on the next update. Basically, I am missing a directory called `/usr/include/c++/4.4/i686-linux-gnu/64` that should contain a subdirectory called `bits` that has the missing include file. Any idea what package should be taking care of this?


  [1]: https://stackoverflow.com/questions/4643197/missing-include-bits-cconfig-h-when-cross-compiling-64-bit-program-on-32-bit/4643464#4643464

Missing include &quot;bits/c++config.h&quot; when cross compiling 64 bit program on 32 bit in Ubuntu

When using Eclipse I browse through the package explorer tree using the keyboard arrows a lot. 

In Windows I can expand a collapsed node by pressing the &lt;kbd&gt;&amp;rarr;&lt;/kbd&gt; key. In Linux I need to press &lt;kbd&gt;Shift&lt;/kbd&gt; + &lt;kbd&gt;&amp;rarr;&lt;/kbd&gt;. Is there a way to reconfigure this so that &lt;kbd&gt;Shift&lt;/kbd&gt; is not required?

Is it possible to use arrow keys alone to expand tree node in package explorer in Eclipse on Linux?

I need to add a cron job thru a script I run to set up a server. I am currently using Ubuntu. I can use `crontab -e` but that will open an editor to edit the current crontab. I want to do this programmatically.

Is it possible to do so?

How do I create a crontab through a script

[MongoDB Suggests][1] that the easy way to handle security is to run it in a trusted environment, given that, &quot;in such a configuration, one must be sure only trusted machines can access database TCP ports.&quot;

What would be the best approach for doing this? Is there a way for mongodb to natively only listen to localhost?

I&#39;m using ubuntu 10.10


  [1]: http://www.mongodb.org/display/DOCS/Security+and+Authentication

How to listen only to localhost on MongoDB

I have two files: `file1` and `file2`. How do I append the contents of `file2` to `file1` so that contents of `file1` persist the process?

Content Type	Original Author	Original Content on Stackoverflow
Question	Halil	View Question on Stackoverflow
Solution 1 - Linux	athspk	View Answer on Stackoverflow
Solution 2 - Linux	joksnet	View Answer on Stackoverflow
Solution 3 - Linux	Ronnie Howell	View Answer on Stackoverflow
Solution 4 - Linux	karlphillip	View Answer on Stackoverflow

What are my environment variables?

Linux Problem Overview

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Convert regular Python string to raw string

Rails Paperclip how to delete attachment?

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