a question that maybe has nothing to do with AIX, but on AIX it causes me to do two commands, while i can do it on linux in one command.

why are files always compressed in .tar.gz ???
i don't see the benefit over just compressing it to .tar

on linux i can decompress .tar.gz files with tar -zxvf file.tar.gz

on Aix i have to to first gunzip file.tar.gz, and thereafter tar -xvf file.tar. is there a way to do it in one command on aix???