====== Linux backup with tar ======

How to make a backup of directories with tar? You can find out in this tutorial.

===== Introduction =====

Individual directory structures can be easily backed up with "tar". You simply create an archive:

<code bash>
tar -cpvlf meinArchiv.tar /Pfad/zu/meinen/Originalen
</code>

An archive is now created with the following buttons:

  * -c : create/create
  * -p : permissions/get me the rights and owner
  * -v : verbose/show what is archived
  * -l : link?/do not follow links to other partitions
  * -f : file/it is a file, in this case a file is created

The path to the archive can be absolute (/path/... ) or relative (./path/... or path/... ).


===== Zipping =====

You could now compress the archive, e.g. with gzip:

<code bash>
gzip meinArchiv.tar
</code>

===== md5sum =====

Before you download the file from a web server, for example, you should calculate the md5 sum to check it. "md5sum" generates a unique number that changes if the downloaded file differs from the original.

The md5 sum of a file can be calculated as follows:

<code bash>
md5sum meinArchiv.tar.gz
</code>

After downloading "myArchive.tar.gz", run the programme again on the target computer and you can compare the figures. 

The output of md5sum can also be redirected to a file and downloaded at the same time. This way you always have the total with the backup:

<code bash>
md5sum meinArchiv.tar > meinArchiv.md5sum.txt
</code>


===== Unpack =====

You can unpack the archive again after it has been gzipped with : 

<code bash>
tar -xzvf meinArchiv.tar.gz
</code>

  * -x : extract/unzip
  * -z : zip/decompress
  * -v : verbose/print on the console what will be unpacked
  * -f : it is a file

If the archive has not been compressed, simply omit the z:

<code bash>
tar -xvf meinArchiv.tar
</code>

If you only want to restore individual files from the archive, enter them after the archive name: 

<code bash>
tar -xvf meinArchiv.tar /Pfad/zu/meinen/Originalen/config.conf
</code>

You can use MidnightCommander (mc) to look into an archive and unpack parts or all of it.

Further help is available:

<code bash>
man tar
</code>