Request exceeded the limit of 10 internal redirects due to probable configuration error.

I upgraded to Apache 2.4.10 and I am getting these errors for sites which used to work:

AH00124: Request exceeded the limit of 10 internal redirects due to probable configuration error. Use 'LimitInternalRecursion' to increase the limit if necessary. Use 'LogLevel debug' to get a backtrace.

One strange thing is these happen only with .htaccess files. So if I use exactly the same configuration but written in vhosts config file such as /etc/apache2/sites-enabled/000-default.conf all works well. So yes, one quick fix is to put it there. But after doing some tests, I found out apache 2.4 does not like when you redirect stuff to index.php but you don't have a rule for index.php itsels. So simply keeping all rules and adding something like RewriteRule ^index\.php$ - [L] fixed the problem.

[UPDATE] On many other cases it seems to work without any trouble or extra rule, but on that particular one not... strange.

kernel: do_IRQ: No irq handler for vector (irq -1)

On a fresh Debian Jessie I kept getting every couple of minutes this error:
do_IRQ: No irq handler for vector (irq -1)
A suggested solution is to add "pci=nomsi,noaer" in /etc/default/grub at GRUB_CMDLINE_LINUX
However,  noaer refers to PCIE Advanced Error Reporting and I don't want only to hide the mess, I want to fix it (if possible).
Only adding pci=nomsi seems to do the trick so far.
Also don't forget to do a update-grub after you edit /etc/default/grub.

Debian 8 does not execute /etc/rc.local

I have just installed a fresh Debian 8 Jessie and then I put something in /etc/rc.local.
To my suprise, after the reboot, the command did not execute.
Log investigation showed:

Failed to start /etc/rc.local Compatibility.
Failed at step EXEC spawning /etc/rc.local: Exec format error

So I simply added "#!/bin/sh -e" in the first line of rc.local and then it worked well.

Youtube mp3 extract in Debian Linux

youtube-dl --extract-audio --audio-format mp3 [URL]

HITACHi Air Conditioner green light turn off

Since last year I have a HITACHI Air Conditioner and the technician told me to clean the filters every two weeks, but he didn't mention anything about the green led. So after a while, this green light turned on, I noticed it has something to do with the filters so I have cleaned them hoping it has some sensor and will turn off automatically. But it didn't. Later I found you have to press the AUTO SWING from the remote while the unit is off. And after 200 hours of functioning it will turn on again to remind you about cleaning the filters.

Pasting source code in friendly format

Here are three tools you can use to paste source codes:

http://codeformatter.blogspot.de
http://hilite.me/
http://markup.su/highlighter/

Mass kill processes in MySQL "show processlist"

So your server load is high you did "SHOW PROCESSLIST;" and you noticed many slow queries and you want to kill them.
If the list is too long to do it manually, you may want to try this way:

<?php

include("mySqlClass.inc.php");

$serv="localhost";
$user="root";
$pass="YOUR_PASS";
$database="SOME_DB";


$link = new mySqlClass();
$link->Connect($serv,$user,$pass,$database);
$result=$link->SqlQuery("SHOW FULL PROCESSLIST");
while ($result->NextRow()) {
    $process_id=$result->field["Id"];
    if ($result->field["Time"]>200) $link->SqlQuery("KILL $process_id");
}   

?>

and the mySqlClass.inc.php:

<?php

class mySqlClass {

  public $query_count;
  public $query_time;

  private $database;
  public $link;
  private $db_connected;

  function __construct()
  {
    $this->query_count = 0;
    $this->query_time = 0;
  }

  public function Connect($host, $user, $password, $database)
  {
    $this->database = $database;

    $this->link = @mysql_connect($host, $user, $password, true);

    if ($this->link)
    {
      if (@mysql_select_db($database, $this->link))
      {
        $this->db_connected = true;
        return true;
      }
    }

    $this->_error(mysql_errno(), mysql_error());
    return false;
  }

  public function SqlQuery($sql)
  {
    $time_start = explode(' ', microtime());

    if (!$this->db_connected) $this->_error(0, 'Error: MySQL DB Not Connected');

    $result_resource = @mysql_query($sql, $this->link);

    if (!$result_resource) $this->_error(@mysql_errno($this->link), @mysql_error($this->link));

    $obj = new SqlQueryResult($result_resource);

    if ($obj->RowCount() > 0)
    {
      // Return the first row of data results
      $result_array = @mysql_fetch_array($result_resource, MYSQL_ASSOC);

      if ($result_array)
      {
        while (list($key, $value) = each($result_array))
        {
          $obj->field[$key] = $value;
        }
      }
    }

    $time_end = explode (' ', microtime());
    $query_time = $time_end[1]+$time_end[0]-$time_start[1]-$time_start[0];
    $this->query_time += $time_end[1] + $time_end[0] - $time_start[1] - $time_start[0];
    $this->query_count++;

    return($obj);
  }

  public function QueryCount()
  {
    return $this->query_count;
  }

  public function QueryTime()
  {
    return $this->query_time;
  }

  private function _error($error_number, $error_text)
  {
    if ($error_number != 1141)
    {
      echo "Error #$error_number: $error_text";
      die();
    }
  }
}


class SqlQueryResult {

  public $field;

  private $result_resource;
  private $num_rows;
  private $current_row;

  function  __construct($result_resource)
  {
    $this->result_resource = $result_resource;
    $this->current_row = 0;
    $this->num_rows = @mysql_num_rows($this->result_resource);
    $this->field = array();
  }

  public function NextRow()
  {
    if ($this->current_row === 0)
    {
      // Row already fetched from SqlQuery() function
      // Do nothing
    }
    else if ($this->num_rows > 0 AND $result_array = @mysql_fetch_array($this->result_resource, MYSQL_ASSOC))
    {
      // This is the next iteration and there is a counted row returned
      // Grab data array
      if ($result_array)
      {
        while (list($key, $value) = each($result_array))
        {
          $this->field[$key] = $value;
        }
      }
    }
    else
    {
      // No more rows, end of data iteration
      // End result
      return false;
    }

    $this->current_row++;

    return true;
  }

  public function RowCount()
  {
    return $this->num_rows;
  }
}