68
70
display version information and exit
73
choose auto (the default), bzip2, pbzip2, or none. The 'auto' option will use pbzip2 if available, otherwise bzip2, and this is the default behavior if the -c option is not used. The difference between bzip2 and pbzip2 is that pbzip2 will utilize all available processors on a multiple-processor system when compressing the archive. Since this processing is done with a 'nice' level of 10, it will only use spare processing capacity that is not being used by other ordinary processes. Still, specifying bzip2 limits the compression process to one processor. If 'none' is specified, the backup archive will be an uncompressed tar file, which is not recommended except for special uses.
71
76
fast integ; use the fast option (indexes only) for the integrity check