In addition to davorgs help, I'd just like to point out that tar on it's own does not compress anything, it simply writes the given files into a common archive file. If you want compression on this archive the easiest way is to specify the -z(for gzip compression) or -j(for bzip2) command line option, e.g. "tar -cvzf <archive> <files>". This is for GNU tar, other variants may use different switches or may not have these options at all, consult your systems tar manpage on that.