.Z files (deletes processed file after compressing/uncompressing)

1. to compress:
   $ compress file_name
2. to uncompress:
   $ uncompress file_name

.gz files (deletes processed file after zipping/unzipping)

1. to zip:
   $ gzip file_name
2. to unzip:
   $ gunzip file_name
3. to open a gz file without deleting the zipped file after unzipping, gunzip (or bunzip2 for bz2 files) with -c (console output) and redirection in order to keep the original file:
   $ gunzip -c file_name.gz > file_name

.tar files

1. to create:
   $ tar cvf file_name.tar files_to_process
2. to extract:
   $ tar xvf file_name.tar
3. to view content:
   $ tar tf file_name.tar

.tgz and .tar.gz files

$ tar xzvf file_name.tgz
does the same as: $ gunzip -c file_name.tar.gz | tar xv

.tar.bz2 files