Use tar.gz on GNU/Linux

To decompress a tar.gz archive use this syntax from command line level:

gzip -dc file_name.tar.gz | tar xf -

If you want to add files to tar archive, use this syntax:

tar -cvf file_name.tar file_to_compress

if you need to use gzip to compress tar archive use additional 'z' parameter:

tar -cvfz file_name.tar.gz file_to_compress

an example:

tar -cvf archive.tar ./directory/*