Cpio

Some of the most straightforward methods for storing the information can be a tar, cpio, or other archive file type.

The method in Listing 16 has the benefit that it works with all versions of tar, cpio, or any other archive tool.

The cpio file format (now supported as a Fedora Core initrd image format) has a long history and operates on a wide range of UNIXes.

The actual archive is created by redirecting the output of cpio into a new file.

Note that cpio will not overwrite files on the destination if they have the same, or newer, modification time.

cpio is another packaging utility along the lines of tar. It is much less common.

As in these newer Linux distributions, the initrd image is also compressed with cpio.

Using the date methods, particularly with tar or cpio, means you can keep a longer-term record with little impact on storage.

Beginning with Fedora Core 3, the default initrd image is a compressed cpio archive file.

To extract files from a cpio archive, use the i command-line option.

There are references to people using cpio and dd for backups.

There are different tools that can be used for the above-mentioned data movement tasks, such as migratepv, cplv, tar, cpio, cp or rsync.

Before you look at that trick, you'll use the same basic method with another archiving tool, cpio.

For example, to create a cpio archive containing specific directories, you might use Listing 11.