Some commonly used packing and unpacking zip and unzip commands

.tar
unpacking: tar xvf FileName.tar
packing: tar cvf FileName.tar DirName
(Note: tar is packing, not compression!)

.gz

Unzip 1: gunzip FileName.gz
Unzip 2: gzip -d FileName.gz
Compress: gzip FileName 

.tar.gz

Unzip: tar zxvf FileName.tar.gz
Compress: tar zcvf FileName.tar.gz DirName

zip

Unzip: unzip FileName.zip
Compress: zip FileName.zip DirName

.rar
Unzip: rar a FileName.rar
Compress: rar e FileName.rar