From Linuxintro

tar is a command to pack files into an archive of the tar format. You can also use it to extract tar archive files.

pack an archive

To create an archive target.tar consisting of the folder /home, use:

tar cvf target.tar /home

unpack an archive

To unpack an archive file, use

tar xvf target.tar

transmit a folder

Thanks to the piping mechanism of Unix, you can also use tar to transmit a folder to another computer:

tar cf - <dir> | ssh <user>@<host> tar -xvf  - -C <dir>

exclude files

tar cvfz filename.tar.gz -X excludefile

In excludefile:

There must not be a slash behind a folder name in the exclude file