When a shell script wraps around an executable, and if you do not want to do anything after the executable completes (that&#39;s a common case for wrapper scripts, in my experience), the correct way to call the executable is:

    exec /the/exe &quot;$@&quot;

The `exec` built-in tells the shell to just give control to the executable without forking.

Practically, that prevents a useless shell process from hanging around in the system until the wrapped process terminates.

That also means that no command can be executed after the `exec` command.

You have to put the `$@` in quotes:

    /the/exe &quot;$@&quot;

How can I generate a random hex color with ruby?

Ruby, Generate a random hex color

Silly question, I want to format an integer so that it appears with the 1000&#39;s separator (,), but also without decimal places and without a leading 0.

My attempts so far have been:

    String.Format(&quot;{0} {1}&quot;, 5, 5000);            // 5 5000
    String.Format(&quot;{0:n} {1:n}&quot;, 5, 5000);        // 5.00 5,000.00
    String.Format(&quot;{0:0,0} {1:0,0}&quot;, 5, 5000);    // 05 5,000

The output I&#39;m after is:

    5 5,000

Is there something obvious that I&#39;m missing?

String.Format an integer to use a thousands separator without decimal places or leading 0 for small integers

I want to write a simple bash script that will act as a wrapper for an executable. How do I pass all the parameters that script receives to the executable? I tried

    /the/exe $@

but this doesn&#39;t work with quoted parameters, eg.

    ./myscript &quot;one big parameter&quot;

runs

    /the/exe one big parameter

which is not the same thing.

Pass bash script parameters to sub-process unchanged

I want to write a simple bash script that will act as a wrapper for an executable. How do I pass all the parameters that script receives to the executable? I tried
<pre><code class="hljs language-bash">/the/exe $@
</code></pre>
but this doesn't work with quoted parameters, eg.
<pre><code class="hljs language-bash">./myscript "one big parameter"
</code></pre>
runs
<pre><code class="hljs language-sql">/the/exe one big parameter
</code></pre>
which is not the same thing.

recently I had to write a little script that parsed VMs in XenServer and as the names of the VMs are mostly with white spaces in e.g Windows XP or Windows Server 2008, I had to trim those white spaces and replace them with underscores _ . I found a simple solution to do this using sed which is great tool when it comes to string manipulation.

    echo &quot;This is just a test&quot; | sed -e &#39;s/ /_/g&#39;

returns

    This_is_just_a_test

Are there other ways to accomplish this?

The easiest way to replace white spaces with (underscores) _ in bash

How can I print the date which is a day before current time in Bash?

Get the date (a day before current time) in Bash

I have a shell script that will let me access global variables inside the script, but when I try to create my own, it responds with: command not found.

    #!/bin/bash
    J = 4
    FACE_NAME = &quot;eig$J.face&quot;
    USER_DB_NAME = &quot;base$J.user&quot;
When I run the above script I get:

    ./test1.sh line 2: J: command not found
    ./test1.sh line 3: FACE_NAME: command not found
    ./test1.sh line 4: USER_DB_NAME: command not found

Any ideas?? I&#39;m using Cygwin under Windows XP.

Bash variable assignment and command not found

What is the simplest/best way to ensure only one instance of a given script is running - assuming it&#39;s Bash on Linux?

At the moment I&#39;m doing:

    ps -C script.name.sh &gt; /dev/null 2&gt;&amp;1 || ./script.name.sh

but it has several issues:

 1. it puts the check outside of script
 2. it doesn&#39;t let me run the same script from separate accounts - which I would like sometimes.
 3. `-C` checks only first 14 characters of process name

Of course, I can write my own pidfile handling, but I sense that there should be a simple way to do it.

What is the best way to ensure only one instance of a Bash script is running?

I have a huge tab-separated file formatted like this

    X column1 column2 column3
    row1 0 1 2
    row2 3 4 5
    row3 6 7 8
    row4 9 10 11

I would like to *transpose* it in an efficient way using only bash commands (I could write a ten or so lines Perl script to do that, but it should be slower to execute than the native bash functions). So the output should look like

    X row1 row2 row3 row4
    column1 0 3 6 9
    column2 1 4 7 10
    column3 2 5 8 11

I thought of a solution like this

    cols=`head -n 1 input | wc -w`
    for (( i=1; i &lt;= $cols; i++))
    do cut -f $i input | tr $&#39;\n&#39; $&#39;\t&#39; | sed -e &quot;s/\t$/\n/g&quot; &gt;&gt; output
    done

But it&#39;s slow and doesn&#39;t seem the most efficient solution. I&#39;ve seen a solution for vi in [this post][1], but it&#39;s still over-slow. Any thoughts/suggestions/brilliant ideas? :-)


  [1]: https://stackoverflow.com/questions/704130/can-i-transpose-a-file-in-vim

An efficient way to transpose a file in Bash

How is it possible to run a [PowerShell][1] script without displaying a window or any other sign to the user?

In other words, the script should run quietly in the background without any sign to the user.

Extra credit for an answer that does not use third party components :)

  [1]: http://en.wikipedia.org/wiki/Windows_PowerShell


How to run a PowerShell script without displaying a window?

I have a simple script blah.py (using Python 2):

    import sys
    print sys.argv[1]

If I execute my script by:

    python c:/..../blah.py argument

It prints argument but if I execute script by:

    blah.py argument

error occurs:
&gt;IndexError...

So arguments do not pass to script.

python.exe in PATH. Folder with blah.py also in PATH.  
python.exe is default program to execute *.py files.

What is the problem?

How to execute Python scripts in Windows?

By using python, how can I check if a website is up? From what I read, I need to check the &quot;HTTP HEAD&quot; and see status code &quot;200 OK&quot;, but how to do so ?

Cheers

### Related
* [How do you send a HEAD HTTP request in Python?][1]


  [1]: https://stackoverflow.com/questions/107405/how-do-you-send-a-head-http-request-in-python

Checking if a website is up via Python

I try to execute the following command :

    mysql AMORE -u username -ppassword -h localhost -e &quot;SELECT  host  FROM amoreconfig&quot;

I store it in a string :

    cmd=&quot;mysql AMORE -u username -ppassword -h localhost -e\&quot;SELECT  host  FROM amoreconfig\&quot;&quot;

Test it : 

    echo $cmd
    mysql AMORE -u username -ppassword -h localhost -e&quot;SELECT host FROM amoreconfig&quot;

Try to execute by doing : 

    $cmd

And I get the help page of mysql :

    mysql  Ver 14.14 Distrib 5.1.31, for pc-linux-gnu (i686) using readline 5.1
    Copyright 2000-2008 MySQL AB, 2008 Sun Microsystems, Inc.
    This software comes with ABSOLUTELY NO WARRANTY. This is free software,
    and you are welcome to modify and redistribute it under the GPL license
    Usage: mysql [OPTIONS] [database]
    (...)

I guess I am doing something plain wrong with the quotes but can&#39;t find out what is the problem. 


How to execute a bash command stored as a string with quotes and asterisk

I&#39;m trying to collect string values in a bash script. What&#39;s the simplest way that I can append string values to a list or array structure such that I can echo them out at the end?

Mutable list or array structure in Bash? How can I easily append to it?

I was wondering if it&#39;s possible to write a function that accepts multiple generic types as follows:

    public int void myfunction(Set&lt;T&gt; a, Set&lt;T&gt; b) {
        return 5;
    }

    Set&lt;Integer&gt; setA = new HashSet&lt;Integer&gt;();
    Set&lt;String&gt; setB = new HashSet&lt;String&gt;();
    int result = myfunction(setA, setB);


Will that work? Does the &lt;T&gt; generic in each parameter mean that each parameter must have the same type T that&#39;s generic?

Java generics: multiple generic parameters?

Call me crazy, but I&#39;m the type of guy that likes constructors with parameters (if needed), as opposed to a constructor with no parameters followed by setting properties. My thought process: if the properties are required to actually construct the object, they should go in the constructor. I get two advantages:

1. I know that when an object is constructed (without error/exception), my object is good.
2. It helps avoid forgetting to set a certain property.

This mindset is starting to hurt me in regards to form/usercontrol development. Imagine this `UserControl`:

    public partial class MyUserControl : UserControl
    {
      public MyUserControl(int parm1, string parm2)
      {
        // We&#39;ll do something with the parms, I promise
        InitializeComponent();
      }
    }

At designtime, if I drop this `UserControl` on a form, I get an `Exception`:

&gt; Failed to create component &#39;MyUserControl&#39; ...&lt;br&gt;
    System.MissingMethodException - No parameterless constructor defined for this object.

It seems like, to me, the only way around that was to add the default constructor (unless someone else knows a way).

    public partial class MyUserControl : UserControl
    {
      public MyUserControl()
      {
        InitializeComponent();
      }

      public MyUserControl(int parm1, string parm2)
      {
        // We&#39;ll do something with the parms, I promise
        InitializeComponent();
      }
    }

The whole point of not including the parameterless constructor was to avoid using it. And I can&#39;t even use the `DesignMode` property to do something like:

    public partial class MyUserControl : UserControl
    {
      public MyUserControl()
      {
        if (this.DesignMode)
        {
          InitializeComponent();
          return;
        }

        throw new Exception(&quot;Use constructor with parameters&quot;);
      }
    }

This doesn&#39;t work either:

    if (LicenseManager.UsageMode == LicenseUsageMode.Designtime)

Fine, moving along ...

I have my parameterless constructor, I can drop it on the form, and the form&#39;s `InitializeComponent` will look like this:

    private void InitializeComponent()
    {
      this.myControl1 = new MyControl();

      // blah, blah
    }

And trust me, because I did it (yes, ignoring the comments Visual Studio generated), I tried messing around and I passed parameters to `InitializeComponent` so that I could pass them to the constructor of `MyControl`.

Which leads me to this:

    public MyForm()
    {
      InitializeComponent(); // Constructed once with no parameters

      // Constructed a second time, what I really want
      this.myControl1 = new MyControl(anInt, aString);  
    }

For me to use a `UserControl` with parameters to the constructor, I have to add a second constructor that I don&#39;t need? And instantiate the control twice?

I feel like I must be doing something wrong. Thoughts? Opinions? Assurance (hopefully)?


&#39;UserControl&#39; constructor with parameters in C#

I got _parameter_ and _argument_ kind of mixed up and did not really pay attention to when to use one and when to use the other.  

Can you please tell me? 


&quot;Parameter&quot; vs &quot;Argument&quot;

In C# you can put a constraint on a generic method like:

    public class A {
        
        public static void Method&lt;T&gt; (T a) where T : new() {
            //...do something...
        }
        
    }

Where you specify that `T` should have a constructor that requires no parameters. I&#39;m wondering whether there is a way to add a constraint like &quot;*there exists a constructor with a `float[,]` parameter?*&quot;

The following code doesn&#39;t compile:

    public class A {
        
        public static void Method&lt;T&gt; (T a) where T : new(float[,] u) {
            //...do something...
        }
        
    }

A workaround is also useful?

Is there a generic constructor with parameter constraint in C#?

I have this line of code:

    &lt;%= link_to &quot;Add to cart&quot;, :controller =&gt; &quot;car&quot;, :action =&gt; &quot;add_to_cart&quot;, :car =&gt; car %&gt;


when im in the add_to_cart method...how can i call the :car please?


    @car = Car.new(params[:car])

That doesn&#39;t work because it says that I&#39;m trying to stringify it.

I don&#39;t understand what&#39;s wrong; because I used this to create new users and it worked fine.

By the way, car is my car object.


 

Content Type	Original Author	Original Content on Stackoverflow
Question	EMP	View Question on Stackoverflow
Solution 1 - Bash	ddaa	View Answer on Stackoverflow
Solution 2 - Bash	sth	View Answer on Stackoverflow

Pass bash script parameters to sub-process unchanged

Bash Problem Overview

Bash Solutions

Solution 1 - Bash

Solution 2 - Bash

String.Format an integer to use a thousands separator without decimal places or leading 0 for small integers

Ruby, Generate a random hex color

Attributions