lubkin@cs.rochester.edu (Saul Lubkin) (11/07/90)
There is an undocumented option to SCO Unix 3.2 v2 tar, that compresses files (using compress) when creating an archive, and that uncompresses them when restoring with tar. Someone posted the undocumented line switch in a previous note that I've lost. Can anyone retrieve this? Thanks, Saul Lubkin
md@sco.COM (Michael Davidson) (11/08/90)
lubkin@cs.rochester.edu (Saul Lubkin) writes: >There is an undocumented option to SCO Unix 3.2 v2 tar, that compresses >files (using compress) when creating an archive, and that uncompresses >them when restoring with tar. Not quite correct - there is an option which will set a flag in the tar header to indicate that a file should be uncompressed automatically when tar extracts it. There is no support in tar for automatically compressing files as they are being archived, using the "C" option when creating a tar archive just sets a flag in the header to indicate that tar should attempt to uncompress the files when they are extracted. The "X" option will extract files but suppresses any attempt to uncompress them.
peter@secyt.UUCP (Pedro Victor Pintus) (11/09/90)
In article <1990Nov6.205259.18525@cs.rochester.edu> lubkin@cs.rochester.edu (Saul Lubkin) writes: >There is an undocumented option to SCO Unix 3.2 v2 tar, that compresses >files (using compress) when creating an archive, and that uncompresses >them when restoring with tar. > >Someone posted the undocumented line switch in a previous note that >I've lost. Can anyone retrieve this? > >Thanks, > > Saul Lubkin IMHO, the use of undocumented options is an unaceptable risk, especially for backup usage, since those undocumented options may (eventually) dissapear in further releases of the software. If you want cut the media usage in archiving, you can tar to a file, then compress the file, then tar the compressed file. This appears (at least to me) to be safer, since there is no dependencies on strange software options. Pedro V. Pintus. (Internet: peter@secyt.ar) Disclaimer: The above text is my personal opinion; my employer has nothing to do with this.