Each time I have to install a new nfs for my IGEP I end up with reading bzip2/bunzip2 or tar manual to get it right. I hope it's gonna stay in my head for a while if I'll write it down here.

• How to extract a cpio archive (to your current directory)?

$ cpio -id < rootfs.cpio

• How to decompress tar file (to your current directory)?

$ tar -xf rootfs.tar

• How to decompress tar.bz2 file (to your current directory)?

$ tar -xjf rootfs.tar.bz2
You don't have to use bzip2, thanks to -j option.

• How to decompress tar.gz file (to your current directory)?

$ tar -xzf rootfs.tar.gz
The -z option stands for gzip.

You can add -v to all of the above commands to get verbose output during process of extraction, It is useful to know that everything is going fine, though it can make the whole process a little bit slower.