Path: utzoo!mnetor!uunet!husc6!mit-eddie!killer!wnp From: wnp@killer.UUCP (Wolf Paul) Newsgroups: comp.unix.questions Subject: Re: cpio Message-ID: <4027@killer.UUCP> Date: 9 May 88 03:35:08 GMT References: <625@mccc.UUCP> Reply-To: wnp@killer.UUCP (Wolf Paul) Distribution: na Organization: The Unix(R) Connection BBS, Dallas, Tx Lines: 27 Keywords: diskette, tape In article <625@mccc.UUCP> pjh@mccc.UUCP (Peter J. Holsberg) writes: > >Do cpio and ctccpio always overwrite anything that is already on the >diskette or tape? If so, is there any 'copy' program that does not? >Thanks. Cpio and things like tar don't check to see if there is data; you need to keep track of what's on the medium you're using. Most tape drivers call a single contiguous recording of data a "volume" or (BSD4.2) a "file system"; most drivers come with a user command to position the tape after a specified volume or file system (i.e. BSD4.2 the command is "fsf"). If your driver does not support this, or if you are using disks, you can somehow keep track of how much data is on a given disk or tape and then use some kind of "skipping" filter to write your cpio output. There was such a program posted to comp.sources.misc a few months ago, I think it was called "bundle". Basically such a program opens the device in read/write mode, and reads or seeks the specified number of bytes before writing its standard input to its standard output. -- Wolf N. Paul * 3387 Sam Rayburn Run * Carrollton TX 75007 * (214) 306-9101 UUCP: ihnp4!killer!dcs!wnp ESL: 62832882 INTERNET: wnp@DESEES.DAS.NET or wnp@dcs.UUCP TLX: 910-280-0585 EES PLANO UD