Find the same files by their size:

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ls -l | awk '$1!~/^d/{if(size[$5]!=""){ print}size[$5]=$8}'

Very useful to delete duplicate photos or videos.

31st March has been declared to World Backup Day please remember to ensure your files are backed up on March 31st!

Some stuff written by myself about backuping different stuff:
Create Backups with tartarus
MySQL Dump
Backup your MBR
Rsync Server

Sure you know, this is a really bad idea;) But if you want to register a domain that contains a fückinß umlaut, this solution will work for bind. But I start with a little explanation, you are not allowed to fill the bind configs with umlauts you should transform them to punycode.

Install transformation tool:

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apt-get install idn

Transform you domain:

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echo www.größte-scheiße.de | idn -a --quiet

The output will be: www.xn--grsste-scheisse-9sb.de

Now you can use the converted string of your domain in the bind configuration files.
If you are using putty please set your Translation to UTF8 otherwise idn will not convert your domain;)

This tiny code will produce a SIGSEGV (Segmentation fault) after compiling and executing

Create file example.c and fill it with this code:

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#include <stdio.h>
 
int main()
{
  char* text = "hello world";
 
  text = 13423;
  printf(text);
}

Compile:

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gcc -o example example.c

Run and get a Segmentation fault:

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./example

Debug Segmentation fault:

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strace ./example

Another really helpful check for your Icinga or Nagios instance.

If your have any windows machines you can check the Windows Update-State. How many Updates you need to install and if you need to reboot your servers after updating them.

Get the Update Script.

Copy the Script to “C:\Program Files\NSClient++\scripts\”

Uncomment the NRPEListener.dll and CheckExternalScripts.dll parameters in your NSC.ini config:

In the [NRPE] section
uncomment following options:

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port=5666
command_timeout=60
allow_arguments=0
use_ssl=1
socket_timeout=30

[External Scripts] section:

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check_win_updates=cscript.exe //T:40 //NoLogo scripts\test-updates.wsf /w:1 /C:10

Restart NSClient Service:

Check the script from windows command line (CMD- the black window;)):

Icinga output (click to resize):

The result (after I installed some Updates:-)) (click to resize):

Icinga-side configurations:

Command definition:

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define command {
    command_name    check_win_updates
    command_line    /usr/lib/nagios/plugins/check_nrpe -H $HOSTADDRESS$ -p 5666 -c check_win_updates
}

Service definition:

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define service {
    hostgroup_name                  check-win-updates
    service_description             Windows Updates
    check_command                   check_win_updates
    use                             generic-service
}

Hostgroups definition:

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define hostgroup {
    hostgroup_name          check-win-updates
    alias                   Windows Updates
    members                 windows2008r2, windows7
}

Check icinga-config and restart the process:

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icinga -v /etc/icinga/icinga.cfg && service icinga reload