I'm not sure where the name 7-Zip came from, but I know it has helped me in more than 7 occasions. ;) I know its a bad joke, I couldn't help myself. Perhaps one of my readers is more knowledgable in the history of the name 7-Zip.
7-Zip is one of the best file compression programs I've used, and the best part - its FREE! It can work with most of the major compression formats such as 7z (natve format), ZIP, GZIP, BZIP2 and TAR. It can also open files compressed with RAR, CAB, ISO, ARJ, LZH, CHM, MSI, WIM, Z, CPIO, RPM, DEB and NSIS. Just some gobbledygook for those who are into compression schemes, you know who you are.
I've used this application to open compressed files from unix systems such as GZ and TAR files, as well as extract files from Linux ISO disc image files. I've also used its command line capabilities to schedule backups for some computer systems.
If you need a file compression program, I highly recommend 7-Zip. You can find it here. It's available for windows, mac and unix. Though only command line versions are available for the unix based systems.
What application do you use for file compression?