Created Sunday 18 July 2010

-tar (-c for create, -x for extract) - tar alone simply creates a collection (Tape ARchive) of uncompressed files.
tar -cvf result.tar file1 file2 file3
tar -xvf file.tar
NOTES: compression algorithms:
-add -j for bzip2 compression (AMAZING for plain english text i.e. 200M down to 14M). result file extension: .tbz or .tar.bz2
-add -z for gzip compression (good for general use). result file extension: .tgz or .tar.gz

-rar (a for add)
rar a output.rar file1 file2 file3
-unrar (e for extract)
unrar e file.rar
ADDITION: see extractrars script in Linux>shell scripting

-zip/unzip
zip output.zip file1 file2 file3
unzip file.zip