Packing and unpacking files
From Linuxintro
Here are the most practical commands to pack and unpack files in a console:
Unpacking
unrar -kb x filename.rar
unzip filename.zip
bunzip2 filename.bz2
tar xvf filename.tar
tar xvzf filename.tar.gz
Packing
tar cvzf targetfile.tar.gz /sourcedir
tar cvf targetfile.tar /sourcedir
When using really large files, for example when you clone a computer it pays to use a program that can use all your processor threads in parallel. pigz is a good choice for that. To draw a backup from your harddisk:
cat /dev/sda | pigz -c >test
Unpacking can then be done with
pigz -d -c test >/dev/sdx