Seems like curl support `--interface` option

    curl --interface eth0 

For anyone that comes here looking for the same answer, but for wlan0 or whatever the non-default interface is on Raspberry/RPi, you&#39;ll need to sudo or run as root. 

In my case I was running eth0 and wlan0, but eth0 was my default NIC. Ping worked without sudo, curl didn&#39;t have verbose enough logging beyond saying the connection timed out and only worked without sudo on eth0. Traceroute finally led me to my answer when the error said &quot;setsockopt SO_BINDTODEVICE: Operation not permitted&quot;

Go types like `Int64` and `String` cannot store null values,
so I found I could use [sql.NullInt64](https://golang.org/pkg/database/sql/#NullInt64) and [sql.NullString](https://golang.org/pkg/database/sql/#NullString) for this.

But when I use these in a Struct,
and generate JSON from the Struct with the [json](https://golang.org/pkg/encoding/json/) package,
then the format is different to when I use regular `Int64` and `String` types.

The JSON has an additional level because the sql.Null*** is also a Struct.

Is there a good workaround for this,
or should I not use NULLs in my SQL database?


How can I work with SQL NULL values and JSON in a good way?

I&#39;m a Laravel newbie and I&#39;m converting a php/jquery app to Laravel. The original code used a JSON array with an ajax POST, which was retrieved like this:

    $json = file_get_contents(&#39;php://input&#39;);
    $data = json_decode($json,true);

I&#39;m doing much the same thing on the POST side, but I don&#39;t see any data coming through in my Laravel $request collection. Is there something special that I need to do to retrieve JSON data structured like this:

    [
        { &quot;name&quot;: &quot;John&quot;, &quot;location&quot;: &quot;Boston&quot; }, 
        { &quot;name&quot;: &quot;Dave&quot;, &quot;location&quot;: &quot;Lancaster&quot; }
    ]


Here is my jQuery ajax POST code (with hard coded data)

    $.ajax({
    	type: &quot;POST&quot;,
    	url: &quot;/people&quot;,
    	data: &#39;[{ &quot;name&quot;: &quot;John&quot;, &quot;location&quot;: &quot;Boston&quot; }, { &quot;name&quot;: &quot;Dave&quot;, &quot;location&quot;: &quot;Lancaster&quot; }]&#39;,
    	dataType: &quot;json&quot;,
    	success:function(data) {
    		$(&#39;#save_message&#39;).html(data.message);
    	} 
    });

Here is the code in my Controller that receives the POST

    public function store(Request $request)
    {
        dd($request-&gt;all());
    }

But all I get is:

&gt; []

Any ideas on how I can retreive my data?

Laravel 5: Retrieve JSON array from $request

I am developing a code in c, which simply FTPs the files on FTP server by using curl utility, by following this 
[example][1]

now i have one simple thing to do, specify curl to use particular interface (IP) of the server for upload, as other interface of the server is associated with other socket connection.

is there any way to do it?


  [1]: http://curl.haxx.se/libcurl/c/ftpupload.html

how to use cURL on specific interface

I am developing a code in c, which simply FTPs the files on FTP server by using curl utility, by following this
<a href="http://curl.haxx.se/libcurl/c/ftpupload.html" target="_blank" rel="noopener noreferrer">example</a>
now i have one simple thing to do, specify curl to use particular interface (IP) of the server for upload, as other interface of the server is associated with other socket connection.
is there any way to do it?

What is the difference between
 

    float f = (float) 99.32 ;

and 

    float f = 99.32f ;


Both of them compiled and ran successfully.

What is the difference between casting to `float` and adding `f` as a suffix when initializing a `float`?

I have a pointer to function, assume any signature.
And I have 5 different functions with same signature.

At run time one of them gets assigned to the pointer, and that function is called.

Without inserting any print statement in those functions, how can I come to know the name of function which the pointer currently points to?





Determining to which function a pointer is pointing in C?

I want to create a program that will simulate an out-of-memory (OOM) situation on a Unix server. I created this super-simple memory eater:

    #include &lt;stdio.h&gt;
    #include &lt;stdlib.h&gt;

    unsigned long long memory_to_eat = 1024 * 50000;
    size_t eaten_memory = 0;
    void *memory = NULL;

    int eat_kilobyte()
    {
        memory = realloc(memory, (eaten_memory * 1024) + 1024);
        if (memory == NULL)
        {
            // realloc failed here - we probably can&#39;t allocate more memory for whatever reason
            return 1;
        }
        else
        {
            eaten_memory++;
            return 0;
        }
    }

    int main(int argc, char **argv)
    {
        printf(&quot;I will try to eat %i kb of ram\n&quot;, memory_to_eat);
        int megabyte = 0;
        while (memory_to_eat &gt; 0)
        {
            memory_to_eat--;
            if (eat_kilobyte())
            {
                printf(&quot;Failed to allocate more memory! Stucked at %i kb :(\n&quot;, eaten_memory);
                return 200;
            }
            if (megabyte++ &gt;= 1024)
            {
                printf(&quot;Eaten 1 MB of ram\n&quot;);
                megabyte = 0;
            }
        }
        printf(&quot;Successfully eaten requested memory!\n&quot;);
        free(memory);
        return 0;
    }

It eats as much memory as defined in `memory_to_eat` which now is exactly 50&amp;nbsp;GB of RAM. It allocates memory by 1&amp;nbsp;MB and prints exactly the point where it fails to allocate more, so that I know which maximum value it managed to eat.

The problem is that it works. Even on a system with 1&amp;nbsp;GB of physical memory.

When I check top I see that the process eats 50&amp;nbsp;GB of virtual memory and only less than 1&amp;nbsp;MB of resident memory. Is there a way to create a memory eater that really does consume it?

System specifications: Linux kernel 3.16 ([Debian][1]) most likely with overcommit enabled (not sure how to check it out) with no swap and virtualized.

  [1]: http://en.wikipedia.org/wiki/Debian


Why doesn&#39;t this memory eater really eat memory?

Why does Clang optimize away the loop in this code

	#include &lt;time.h&gt;
	#include &lt;stdio.h&gt;

	static size_t const N = 1 &lt;&lt; 27;
	static double arr[N] = { /* initialize to zero */ };

	int main()
	{
		clock_t const start = clock();
		for (int i = 0; i &lt; N; ++i) { arr[i] *= 1.0; }
		printf(&quot;%u ms\n&quot;, (unsigned)(clock() - start) * 1000 / CLOCKS_PER_SEC);
	}

but not the loop in this code?

	#include &lt;time.h&gt;
	#include &lt;stdio.h&gt;

	static size_t const N = 1 &lt;&lt; 27;
	static double arr[N] = { /* initialize to zero */ };

	int main()
	{
		clock_t const start = clock();
		for (int i = 0; i &lt; N; ++i) { arr[i] += 0.0; }
		printf(&quot;%u ms\n&quot;, (unsigned)(clock() - start) * 1000 / CLOCKS_PER_SEC);
	}

(Tagging as both C and C++ because I would like to know if the answer is different for each.)

Why does Clang optimize away x * 1.0 but NOT x + 0.0?

Consider the following program (see live demo [here][1]).

    #include &lt;stdio.h&gt;
    int main(void)
    {
          int ;  // Missing variable name
          puts(&quot;Surprise&quot;);
    }

My compiler, gcc 4.8.1, gives the below warning:

&gt; [Warning] useless type name in empty declaration [enabled by default]

Why does it compile fine? Shouldn&#39;t I get a compiler error? g++ 4.8.1 gives the following error when I compile it as a C++ program:

&gt; [Error] declaration does not declare anything [-fpermissive]

  [1]: http://ideone.com/504P4P


Why does `int ;` compile fine in C, but not in C++?

I am trying to debug a script which takes command line arguments as an input. Arguments are text files in the same directory. Script gets file names from sys.argv list. My problem is I cannot launch the script with arguments in pycharm.

I have tried to enter arguments into &quot;Script parameters&quot; field in &quot;Run&quot; &gt; &quot;Edit configuration&quot; menu like so:

    -s&#39;file1.txt&#39;, -s&#39;file2.txt&#39;

But it did not work. How do I launch my script with arguments?

P.S. I am on Ubuntu

Pycharm and sys.argv arguments

How to move a line of text up/down in [Nano linux command line editor](http://www.nano-editor.org/)? 

Is there any analogue way to do that as in [IntelliJ Idea](https://www.jetbrains.com/idea/help/adding-deleting-and-moving-lines.html#d1591098e152):

1. Place the caret at the line to be moved.
2. Do one of the following:

On the main menu, choose `Code | Move Line Up or Code | Move Line Down`.

Press &lt;kbd&gt;Shift&lt;/kbd&gt;+&lt;kbd&gt;Alt&lt;/kbd&gt;+&lt;kbd&gt;Up&lt;/kbd&gt; or &lt;kbd&gt;Shift&lt;/kbd&gt;+&lt;kbd&gt;Alt&lt;/kbd&gt;+&lt;kbd&gt;Down&lt;/kbd&gt;.

Move whole line up/down shortcut in nano (analogue to intelliJ or Visual Studio)

I want to send a `PING` to Redis to check if the connection is working, now I could just install `redis-cli`, but I don&#39;t want to and `curl` is already there. So how can I abuse `curl` to do that? Basically I need to turn off what&#39;s send here:

    &gt; GET / HTTP/1.1
    &gt; User-Agent: curl/7.22.0 (x86_64-pc-linux-gnu) libcurl/7.22.0 OpenSSL/1.0.1 zlib/1.2.3.4 libidn/1.23 librtmp/2.3
    &gt; Host: localhost:6379
    &gt; Accept: */*
    &gt; 
    -ERR wrong number of arguments for &#39;get&#39; command
    -ERR unknown command &#39;User-Agent:&#39;
    -ERR unknown command &#39;Host:&#39;
    -ERR unknown command &#39;Accept:&#39;

I was able to get rid of the `User-Agent` altogether by adding `-A &quot;&quot;`, but I can&#39;t find anything else for the rest. Any idea how I can do that?

Abuse cURL to communicate with Redis

I&#39;m trying to find files modified in last x minutes, for example in the last hour. Many forums and tutorials on the net suggest to use the find command with the -mmin option, like this:

`find . -mmin -60 |xargs ls -l`

However, this command did not work for me as expected. As you can see from the following listing, it also shows files modified earlier than 1 hour ago:

    -rw------- 1 user user   9065 Oct 28 23:13 1446070435.V902I67a5567M283852.harvester
    -rw------- 1 user user   1331 Oct 29 01:10 1446077402.V902I67a5b34M538793.harvester
    -rw------- 1 user user   1615 Oct 29 01:36 1446078983.V902I67a5b35M267251.harvester
    -rw------- 1 user user  72365 Oct 29 02:27 1446082022.V902I67a5b36M873811.harvester
    -rw------- 1 user user  69102 Oct 29 02:27 1446082024.V902I67a5b37M142247.harvester
    -rw------- 1 user user   2611 Oct 29 02:34 1446082482.V902I67a5b38M258101.harvester
    -rw------- 1 user user   2612 Oct 29 02:34 1446082485.V902I67a5b39M607107.harvester
    -rw------- 1 user user   2600 Oct 29 02:34 1446082488.V902I67a5b3aM465574.harvester
    -rw------- 1 user user  10779 Oct 29 03:27 1446085622.V902I67a5b3bM110329.harvester
    -rw------- 1 user user   5836 Oct 29 03:27 1446085623.V902I67a5b3cM254104.harvester
    -rw------- 1 user user   8970 Oct 29 04:27 1446089232.V902I67a5b3dM936339.harvester
    -rw------- 1 user user 165393 Oct 29 06:10 1446095400.V902I67a5b3eM290158.harvester
    -rw------- 1 user user 105054 Oct 29 06:10 1446095430.V902I67a5b3fM265065.harvester
    -rw------- 1 user user   1615 Oct 29 06:24 1446096244.V902I67a5b40M55701.harvester
    -rw------- 1 user user   1620 Oct 29 06:24 1446096292.V902I67a5b41M337769.harvester
    -rw------- 1 user user  10436 Oct 29 06:36 1446096973.V902I67a5b42M707215.harvester
    -rw------- 1 user user   7150 Oct 29 06:36 1446097019.V902I67a5b43M415731.harvester
    -rw------- 1 user user   4357 Oct 29 06:39 1446097194.V902I67a5b56M446687.harvester
    -rw------- 1 user user   4283 Oct 29 06:39 1446097195.V902I67a5b57M957052.harvester
    -rw------- 1 user user   4393 Oct 29 06:39 1446097197.V902I67a5b58M774506.harvester
    -rw------- 1 user user   4264 Oct 29 06:39 1446097198.V902I67a5b59M532213.harvester
    -rw------- 1 user user   4272 Oct 29 06:40 1446097201.V902I67a5b5aM534679.harvester
    -rw------- 1 user user   4274 Oct 29 06:40 1446097228.V902I67a5b5dM363553.harvester
    -rw------- 1 user user  20905 Oct 29 06:44 1446097455.V902I67a5b5eM918314.harvester

Actually, it just listed all files in the current directory. We can take one of these files as an example and check if its modification time is really as displayed by the ls command:

    stat 1446070435.V902I67a5567M283852.harvester

      File: ‘1446070435.V902I67a5567M283852.harvester’
      Size: 9065      	Blocks: 24         IO Block: 4096   regular file
    Device: 902h/2306d	Inode: 108680551   Links: 1
    Access: (0600/-rw-------)  Uid: ( 1001/   user)   Gid: ( 1027/   user)
    Access: 2015-10-28 23:13:55.281515368 +0100
    Modify: 2015-10-28 23:13:55.281515368 +0100
    Change: 2015-10-28 23:13:55.313515539 +0100

As we can see, this file was definitely last modified *earlier* than 1 hour ago! I also tried `find -mmin 60` or `find -mmin +60`, but it did not work either.

Why is this happening and how to use the find command correctly?

How to find files modified in last x minutes (find -mmin does not work as expected)

I&#39;ve installed PHP 7 using [this repo][1], but when I try to run ``composer install``, it&#39;s giving this error:

&gt; - [package] requires ext-curl * -&gt; the requested PHP extension curl is missing from your system.

With PHP 5, you can easily install it by running the ``yum`` or ``apt-get install php5-curl`` command, but I can&#39;t find how to install the PHP 7 equivalent.

How do I install ext-curl for PHP 7?

  [1]: http://php7.zend.com/repo.php

How do I install the ext-curl extension with PHP 7?

Consider the curl command below, is it possible to allow newline in JSON (without the minify) and execute directly in bash (Mac/Ubuntu)

    curl -0 -v -X POST http://www.example.com/api/users \
    -H &quot;Expect:&quot; \
    -H &#39;Content-Type: text/json; charset=utf-8&#39; \
    -d \
    &#39;
    {
    	&quot;field1&quot;: &quot;test&quot;,
    	&quot;field2&quot;: {
    		&quot;foo&quot;: &quot;bar&quot;
    	}
    }&#39;

When I run the command above, seems error occurred at the `second {`
How to fix the above command?

**Updated**: actually I was able to run the command without issue previously, not sure why problem happen recently.

Curl with multiline of JSON

So I have a very simple bash script that is curl&#39;ing to an auth server for a header. The header url is written to a var and then used in the next curl call. When using the var set in the first curl call I am getting &quot;curl: (3) Illegal characters found in URL&quot;. I am able to echo the var and all looks good, I am even able to reset the var (in my example below) and it works.

**The Bash script**


    URL=$(curl -i -X GET -H &quot;X-Auth-User: MyUserna,e&quot; -H &quot;X-Auth-Key: MyAPIKey&quot; &quot;https://urlToAuthServer.tld/auth/v1.0/&quot; | grep &quot;X-Storage-Url:&quot; | awk &#39;{print $2}&#39;)
    
    curl -X GET -H &quot;X-Auth-Token: MyAuthTok&quot; &quot;${URL}/folder/myfile.txt&quot; -o ./myfile.txt


**When running the above example I get:**

    curl: (3) Illegal characters found in URL

**The URL var looks like this (no illegal chars)**

    https://somesecureurl.com/auth/AUTH_67383834-45245453-g34g34t5-34534

**When I do this in terminal it works:**
   &gt;$ URL=$(curl -i -X GET -H &quot;X-Auth-User: MyUserna,e&quot; -H &quot;X-Auth-Key: MyAPIKey&quot; &quot;https://urlToAuthServer.tld/auth/v1.0/&quot; | grep &quot;X-Storage-Url:&quot; | awk &#39;{print $2}&#39;)
   
&gt;$ echo $URL
   
&gt; https://somesecureurl.com/auth/AUTH_67383834-45245453-g34g34t5-34534

Now I copy and paste the string and reasign it to URL like so (again all in terminal):

    &gt;$ URL=&quot;https://somesecureurl.com/auth/AUTH_67383834-45245453-g34g34t5-34534&quot;
    &gt;$ curl -X GET -H &quot;X-Auth-Token: MyAuthTok&quot; &quot;${URL}/folder/myfile.txt&quot; -o ./myfile.txt

It works.

So why am I getting the &quot;curl: (3) Illegal characters found in URL&quot; error in the first example?

**Update**
I ran this:
`printf %s &quot;$URL&quot; | xxd`

Here is the output (addressed changed up you get the idea)

    0000000: 6874 7470 733a 2f2f 6461 6c30 352e 6f62  https://server.ob
    0000010: 6a65 6374 7374 6f72 6167 652e 736f 6674  jectstorage.lite
    0000020: 6c61 7965 722e 6e65 742f 7631 2f41 5554  sabers.com/v1/AUT
    0000030: 485f 6665 3235 3339 3434 2d38 6433 322d  H_aE2563981-7d32-
    0000040: 3432 3138 2d61 6566 632d 6665 6638 3465  4201-bdoi-fef94a
    0000050: 6166 3331 6232 0d                        ag11c8.

 

Using curl in a bash script and getting curl: (3) Illegal characters found in URL

I&#39;m working with an API and I have to send a POST request. I know how to set a header (-H) and (-d) is the body, but what is &quot;--user&quot;.

If I submit this with Postman, or in a text editor with axios or just regular XMLRequest, where do I add this?

The docs say it is for regular http auth.

    curl -X POST -H &quot;Content-Type: application/json&quot; \
         --user &quot;&lt;client_id&gt;:&lt;client_secret&gt;&quot; \
         -d &#39;{&quot;grant_type&quot;: &quot;client_credentials&quot;, &quot;scope&quot;: &quot;public&quot;}&#39; \
         ...



Content Type	Original Author	Original Content on Stackoverflow
Question	madiha malik	View Question on Stackoverflow
Solution 1 - C	MrFreezer	View Answer on Stackoverflow
Solution 2 - C	Brandocious	View Answer on Stackoverflow

how to use cURL on specific interface

C Problem Overview

C Solutions

Solution 1 - C

Solution 2 - C

Laravel 5: Retrieve JSON array from $request

How can I work with SQL NULL values and JSON in a good way?

Attributions