Examining bru Archives

Examining bru Archives

The "table of contents" flag, -t, displays the contents of a bru archive:

bru -t

You can combine this with the -v option for more information:

bru -tv

Use up to four "v" arguments for the most verbose output possible. Refer to bru(1) for more information.

Comparing Archived Files

You can compare files that are archived with the original files.

With bru, use the -d option. For example:

bru -d /usr

If you specify a single -d, bru reports when it discovers that a regular file's size or contents have changed since the archive was made.

If you use -dd, bru reports additional differences in modification dates, access modes, number of links for non-directory files, differences in the contents of symbolic links, owner IDs, and group IDs.

If you specify -ddd, bru reports additional differences in major and minor devices for special files and time of last access for regular files.

If you use -dddd, bru reports all differences except the time of the last status change, major and minor device numbers for non-special files, and size differences for directories. Usually, -dddd provides information that is meaningful only when verifying a full backup of a relatively static filesystem.

Inspecting an Archive for Consistency

The bru program provides an option, -i, to inspect an archive for internal consistency and data integrity. For example:

bru -i

If you add -vv, bru prints information from the archive header block:

bru -ivv

Neither tar nor cpio provides this sort of check. However, listing the contents of an archive is usually sufficient. Also, a reasonable check is to extract the files in the archive while sending the output to /dev/null.