unmkfs Command unmkfs Create a prototype file system unmkfs [-prefix] directory nblocks [file] unmkfs scans directory and builds prototype files with which you can build file systems on backup disks. If prefix is given, it creates files prefix.p01, prefix.p02, etc. If it is not given, unmkfs writes its output to the standard-out- put device. nblocks gives the maximum size of a prototype file. COHERENT current defines a block as being 512 bytes (half a kilobyte); thus, to make the maximum size of a prototype file 10 kilobytes, set nblocks to 20. The file option tells unmkfs to suppress all files in directory that are older than file. If it is not used, then unmkfs builds prototypes for all files in directory. unmkfs provides a useful way to back up file systems onto floppy disks. To do this, perform the following steps: 1. unmkfs a directory, producing prototype files. 2. Format one floppy disk for each prototype file. 3. Using the prototype files in sucession, mkfs each floppy disk. This puts the indicated files onto floppy disk, preserving links. Later, you can use the command cpdir to restore all the files from the floppy disks, or you can use cp to restore individual files. ***** See Also ***** commands, mkfs ***** Notes ***** unmkfs builds a file system in memory as it does its work. With large directory structures, it can run out of memory. COHERENT Lexicon Page 1