cpio command

One of the more popular generic backup utilities in use presently is the cpio command. In huge part, its popularity is due to its capability to append backup volumes and span tapes, permitting creating incremental backup sets and full system backups without losing data integrity.

cpio permits   to copy files into and out of a cpio archive. The term cpio stands for "copy in/out". A cpio copies files to and from an archive file or another directory hierarchy. There are two major options to cpio that determine its mode of operation.

These modes are used to make an archive (cpio -o) and extract files from an archive (cpio -i)

c          -   For portability, write header information in ASCII Character form. Always use this option should be used whenever the origin and destination machines are of various categories.

c    -     (copy out) Reads a list of pathnames from the standard input and copies those files onto the standard output together within pathname and status information. By default Output is padded to a 512- byte boundary.

i           -  (copy in) Extracts files from the standard input, that is supposed to be the product of a previous cpio -o. Only files with names which match the wildcard patterns are selected.

v    -     Lists the files processed, or with -t, provide an 'ls -l' style table of contents listing.

t           -   Prints a table of contents of the input. No files are made.

b    -     Sets the I/O block size to 5120 bytes. Originally the block size is 512 bytes.

m  -      MESSAGE, -message=MESSAGE Prints MESSAGE whenever the end of a volume of the backup media (like as a tape or a floppy disk) is reached, to prompt the user to insert a new volume.

If MESSAGE holds the string "%d", it is replaced through the current volume number (starting at 1).

-a  -      Suppresses absolute filenames. The leading "/" character is removed from the filename in during copy- in.

If a pattern is given, it should match the associative (rather than the absolute) pathname.

Note: Within linux this -a, option is different; here it is used to append to an existing archive. Just works in copy- out mode. The archive should be a disk file specified within the -O or -F (-file) option.