You want

    ./script 2&gt;&amp;1 1&gt;/dev/null | ./other-script


The order here is important. Let&#39;s assume stdin (fd 0), stdout (fd 1) and stderr (fd 2) are all connected to a tty initially, so 

    0: /dev/tty, 1: /dev/tty, 2: /dev/tty

The first thing that gets set up is the pipe. other-script&#39;s stdin gets connected to the pipe, and script&#39;s stdout gets connected to the pipe, so script&#39;s file descriptors so far look like:

    0: /dev/tty, 1: pipe, 2: /dev/tty

Next, the redirections occur, from left to right. `2&gt;&amp;1` makes fd 2 go wherever fd 1 is currently going, which is the pipe.

    0: /dev/tty, 1: pipe, 2: pipe

Lastly, `1&gt;/dev/null` redirects fd1 to `/dev/null`

    0: /dev/tty, 1: /dev/null, 2: pipe

End result, script&#39;s stdout is silenced, and its stderr is sent through the pipe, which ends up in other-script&#39;s stdin.

Also see http://bash-hackers.org/wiki/doku.php/howto/redirection_tutorial

Also note that `1&gt;/dev/null` is synonymous to, but more explicit than `&gt;/dev/null`


How about this:

    ./script 3&gt;&amp;1 1&gt;/dev/null 2&gt;&amp;3 | ./other-script

The idea is to &quot;backup&quot; stdout descriptor, close the original stdout and then redirect strerr to saved stdout.

Its much similar to the solution provided by geirha, but its more explicit (bash coding can easily become very obscured).

Well, that&#39;s because you can&#39;t.  STDOUT and STDERR are just two files, represented by file descriptors, which are just integers, specifically 1 and 2.

What you&#39;re asking is to set descriptor 2 to `/dev/null`, then set descriptor 3 to the same file descriptor 2 and have that output go somewhere else.



Having spent a number of years working primarily with MS SQL Server (and hence SQL Server Management Studio for common tasks), I am now beginning to work with MySql. To date I have been using &lt;em&gt;MySQL Workbench&lt;/em&gt; and am generally happy with it.

I would, however, like to be able to assign &lt;strong&gt;custom keyboard shortcuts&lt;/strong&gt; for certain commands (e.g. commands from &lt;a href=&quot;http://dev.mysql.com/doc/workbench/en/wb-keys.html&quot;&gt;this list&lt;/a&gt;). For example, I&#39;d prefer to stick to the MS-SQL approach of &#39;F5&#39; to execute queries, rather than hitting &#39;Modifier+Return&#39;. I haven&#39;t yet come across a simple way to do this. My questions are then:
&lt;ul&gt;
&lt;li&gt;Is this possible somehow in MySQL Workbench (e.g. additional plugin)?&lt;/li&gt;
&lt;li&gt;If not, do any of the alternatives to MySQL Workbench offer this functionality?&lt;/li&gt;
&lt;/ul&gt;

Environment:
&lt;ul&gt;
&lt;li&gt;Ubuntu 12.04 LTS, 32 bit&lt;/li&gt;
&lt;li&gt;MySQL server version 5.5.24-0ubuntu0.12.04.1&lt;/li&gt;
&lt;li&gt;MySQL Workbench Version 5.2.38, rev 8753&lt;/li&gt;
&lt;/ul&gt;

Cheers!

Customizing Keyboard Shortcuts in MySql Workbench

This information should be easy to find, but I haven&#39;t had any luck.

When I have a `BEGIN - END` block in a PL/SQL, does it behave as an atomic transaction, that will try to commit on hitting the `END` block and if anything goes wrong rolls back the changes?

If not, how do I make sure that the code inside the BEGIN - END block behaves like an atomic transaction and how does the block behave &quot;by default&quot;?

EDIT: I am running from a stored procedure and I am using an implicit block, I think.

BEGIN - END block atomic transactions in PL/SQL

I saw this interesting question at a comment on [cyberciti.biz](http://www.cyberciti.biz/faq/how-to-redirect-output-and-errors-to-devnull/).

That I found I even can&#39;t find a flexible way to do this in one-line command with sh.

As far my thought for the solution is:

    tmp_file=`mktemp`
    (./script 2&gt;$tmp_file &gt;/dev/null; cat $tmp_file) | ./other-script
    rm tmp_file

But you see, this is not synchronous, and fatally, it&#39;s so ugly.


Welcome to share you mind about this. :)


Shell: redirect stdout to /dev/null and stderr to stdout

I saw this interesting question at a comment on <a href="http://www.cyberciti.biz/faq/how-to-redirect-output-and-errors-to-devnull/" target="_blank" rel="noopener noreferrer">cyberciti.biz</a>.
That I found I even can't find a flexible way to do this in one-line command with sh.
As far my thought for the solution is:
<pre><code class="hljs language-bash">tmp_file=`mktemp`
(./script 2>$tmp_file >/dev/null; cat $tmp_file) | ./other-script
rm tmp_file
</code></pre>
But you see, this is not synchronous, and fatally, it's so ugly.
Welcome to share you mind about this. :)

I am trying to print the results of an MD5 hash to the console and it is working for the most part. To ensure correctness, I used an online MD5 calculator to compare results. Most of the characters are the same, but a few are missing in mine and they are are all leading zeroes.

Let me explain. The result is a 16 byte unsigned char *. I print each of these bytes one by one. Each byte prints TWO characters to the screen. However, if the first character out of the two is a zero, it does not print the zero. 

    printk(&quot;%x&quot;, result);

Result is of type unsigned char*. Am I formatting it properly or am I missing something?

Printing leading zeroes for hexadecimal in C

    top -c

Top lists all the processes, there are good options to filter the processes by username by using the option -u &lt;username&gt; but I am wondering if there is any easy way to filter the processes based on processname listed under COMMAND column of the top output.

For Example I would want like top -some option -substring of processname and top displays pids only having this substring in its command name


top -c command in linux to filter processes listed based on processname

Note: When originally posted I was trying to install maven2. Since the main answer is for maven3 I have updated the title. The rest of the question remains as it was originally posted.

I&#39;m trying to install maven2 on a redhat linux box using the command

     yum install maven2

but yum doesn&#39;t seem to be able to find maven2.

    No package maven2 available

 I&#39;ve run across other posts about this topic, but the answer to the following post suggests to add repos. I add said repos, but run into errors after adding them.

https://stackoverflow.com/questions/6298865/how-to-install-maven-into-red-hat-linux-enterprise-addition-6

I can only access this box via command line so simply downloading maven from their website is difficult for me.

How to install maven on redhat linux

I tried installing Intel MPI Benchmark on my computer and I got this error:

    fork: retry: Resource temporarily unavailable

Then I received this error again when I ran `ls` and `top` command.

What is causing this error?

Configuration of my machine:

    Dell precision T7500
    Scientific Linux release 6.2 (Carbon)


fork: retry: Resource temporarily unavailable

In UNIX/LINUX, is there an easy way to track the time a command takes?


Track the time a command takes in UNIX/LINUX?

I want to write a bash script which takes different arguments. It should be used like normal linux console programs:

    my_bash_script -p 2 -l 5 -t 20

So the value 2 should be saved in a variable called pages and the parameter l should be saved in a variable called length and the value 20 should be saved in a variable time.

What is the best way to do this?

Command line arguments in Bash

When I try to do a basic `git add *.erb` (or any simple wildcard expressions) git is not recognizing it (them). As a side-note, I have never done this before so I&#39;m sure it&#39;s a rookie mistake, but I&#39;ve found no help in other SO posts or my school&#39;s alumni listserv so I thought this post may be appropriate.

For (a different) example, **git status** is giving me:

    #	modified:   config/routes.rb
    #	modified:   spec/models/question_spec.rb

I wanted to only stage the routes file, so I tried **git add *s.rb** and no dice. I am in the root of the app...do I need to be in the directory that contains the file(s) I&#39;m trying to apply the wildcard expression to? That would be painful, but...actually...it just worked.

Hope this doesn&#39;t have to be a separate post, but is there an easier way to use wildcards where you don&#39;t have to cd into the specific directory?

&quot;git add&quot; using wildcard is not functioning as I hoped - must I cd into specific directories?

I&#39;m trying to refine my code by getting rid of unnecessary white spaces, empty lines, and having parentheses balanced with a space in between them, so:

        int a = 4;
        if ((a==4) ||   (b==5))

        a++   ;

should change to:

        int a = 4;
        if ( (a==4) || (b==5) )
        a++ ;

It does work for the brackets and empty lines. However, it forgets to reduce the multiple spaces to one space:

        int a = 4;
        if ( (a==4) ||   (b==5) )
        a++    ;

Here is my script:

        #!/bin/bash
        # Script to refine code
        #
        filename=read.txt

        sed &#39;s/((/( (/g&#39; $filename &gt; new.txt
        mv new.txt $filename

        sed &#39;s/))/) )/g&#39; $filename &gt; new.txt
        mv new.txt $filename

        sed &#39;s/ +/ /g&#39; $filename &gt; new.txt
        mv new.txt $filename

        sed &#39;/^$/d&#39; $filename &gt; new.txt
        mv new.txt $filename

Also, is there a way to make this script more concise, e.g. removing or reducing the number of commands?

&#39;+&#39; (one or more occurrences) not working with &#39;sed&#39; command

Suppose I have a large number of files in a directory with `.txt` extension.

How can I change the extension of all these files to `.c` using the following command line environments:

* Powershell in Windows 
* cmd/DOS in Windows
* The terminal in bash


How do I change the extension of many files in a directory?

I have to write a function in bash. The function will take about 7 arguments. I know that I can call a function like this:

To call a function with parameters:

    function_name $arg1 $arg2

And I can refer my parameters like this inside the function:

    function_name () {
       echo &quot;Parameter #1 is $1&quot;
    }

My question is, is there a better way refer to the parameters inside the function? Can I avoid the $1, $2, $3, .... thing and simply use the $arg1, $arg2, ...?

Is there a proper method for this or do I need to re-assign these parameters to some other variables inside the function? E.g.:

    function_name () {
       $ARG1=$1
       echo &quot;Parameter #1 is $ARG1&quot;
    }

Any example would be much appreciated. 

Is there a way to avoid positional arguments in bash?

I need to run a java jar in server in order to communicate between two applications. I have written two shell scripts to run it, but once I start up that script I can&#39;t shut down / terminate the process. If I press &lt;kbd&gt;ctrl&lt;/kbd&gt;+&lt;kbd&gt;C&lt;/kbd&gt; or close the console, the server will shut down. Could anyone help me how to modify this script to run as a normal server?

     #!/bin/sh
    java -jar /web/server.jar
    echo $! 
    #&gt; startupApp.pid



Run java jar file on a server as background process

All of us probably know `.bat` for Batch files.

But what is the file extension for **PowerShell 3** scripts?

I found `.ps1` and some other endings but they&#39;re only for version 1. 

File extension for PowerShell 3

How can I test if a command outputs an empty string?

Test if a command outputs an empty string

What&#39;s wrong with the following code?

    name=&#39;$filename | cut -f1 -d&#39;.&#39;&#39;

As is, I get the literal string `$filename | cut -f1 -d&#39;.&#39;`, but if I remove the quotes I don&#39;t get anything. Meanwhile, typing

    &quot;test.exe&quot; | cut -f1 -d&#39;.&#39;

in a shell gives me the output I want, `test`. I already know `$filename` has been assigned the right value. What I want to do is assign to a variable the filename without the extension.

How can I remove the extension of a filename in a shell script?

Is there such a thing in `bash` or at least something similar (work-around) like forward declarations, well known in C / C++, for instance?

Or there is so such thing because for example it is always executed in one pass (line after line)?

If there are no forward declarations, what should I do to make my script easier to read. It is rather long and these function definitions at the beginning, mixed with global variables, make my script look ugly and hard to read / understand)? I am asking to learn some well-known / best practices for such cases.


----------------------------------


For example:

    # something like forward declaration
    function func

    # execution of the function
    func
    
    # definition of func
    function func
    {
        echo 123
    }


Forward function declarations in a Bash or a Shell script?

I have a script that uses `sh` shell. I get an error in the line that uses the `source` command. It seems `source` is not included in my `sh` shell. 

If I explicitly try to run `source` from shell I get:

    sh: 1: source: not found

Should I somehow install &quot;source&quot;? Do I have a wrong version of `sh`?



source command not found in sh shell

So I am not experienced in dealing with a plethora of file types, and I haven&#39;t been able to find much info on exactly what `.sh` files are. Here&#39;s what I&#39;m trying to do:

I&#39;m trying to download map data sets which are arranged in tiles that can be downloaded individually: http://daymet.ornl.gov/gridded

In order to download a range of tiles at once, they say to download their script, which eventually leads to `daymet-nc-retrieval.sh`: https://github.com/daymet/scripts/blob/master/Bash/daymet-nc-retrieval.sh

So, what exactly am I supposed to do with this code? The website doesn&#39;t provide further instructions, assuming users know what to do with it. I&#39;m guessing you&#39;re supposed to paste the code in to some other unmentioned application for a browser (using Chrome or Firefox in this case)? It almost looks like something that could be pasted in to Firefox/Greasemonkey, but not quite. Just by a quick Google on the file type I haven&#39;t been able to get heads or tails on it. 

I&#39;m sure there&#39;s a simple explanation on what to do with these files out there, but it seems to be buried in plenty of posts where people are already assuming you know what to do with these files. Anyone willing to just simply say what needs to be done from square one after getting to the page with the code to actually implementing it? Thanks.

What&#39;s a .sh file?

I currently use a `.bat` file that is utilized to invoke a java file. If I wanted to utilize the same functionality on Mac OS what format changes would I make? (unless the `.bat` equivalent on Mac OS is the `.sh` format?)

    java -cp  &quot;.;.\supportlibraries\Framework_Core.jar;.\supportlibraries\Framework_DataTable.jar;.\supportlibraries\Framework_Reporting.jar;.\supportlibraries\Framework_Utilities.jar;.\supportlibraries\poi-3.8-20120326.jar;D:\downloads\Selenium 2.0\selenium-server-standalone-2.19.0.jar&quot; allocator.testTrack

Any assistance would be appreciated.

Content Type	Original Author	Original Content on Stackoverflow
Question	shouya	View Question on Stackoverflow
Solution 1 - Linux	geirha	View Answer on Stackoverflow
Solution 2 - Linux	Zaar Hai	View Answer on Stackoverflow
Solution 3 - Linux	Charlie Martin	View Answer on Stackoverflow

Shell: redirect stdout to /dev/null and stderr to stdout

Linux Problem Overview

Linux Solutions

Solution 1 - Linux

Solution 2 - Linux

Solution 3 - Linux

BEGIN - END block atomic transactions in PL/SQL

Customizing Keyboard Shortcuts in MySql Workbench

Attributions