The mtree utility compares a file hierarchy against a specification, creates a specification for a file hierarchy, or modifies a specification. This specification can be controlled by the user, but typically includes file/directory/symlink names, ownership information, permission bits, and so forth. It may optionally also include various hashes, such as SHA-256 or MD5.

This mtree utility can understand its own files, as well as those generated by the FreeBSD mtree (in Debian as fmtree in freebsd-buildutils and freebsd-glue) and bsdtar/libarchive.