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MTREE(5) File Formats Manual MTREE(5)


mtreeformat of mtree dir hierarchy files


The mtree format is a textual format that describes a collection of filesystem objects. Such files are typically used to create or verify directory hierarchies.

General Format

An mtree file consists of a series of lines, each providing information about a single filesystem object. Leading whitespace is always ignored.

When encoding file or pathnames, any backslash character or character outside of the 95 printable ASCII characters must be encoded as a a backslash followed by three octal digits. When reading mtree files, any appearance of a backslash followed by three octal digits should be converted into the corresponding character.

Each line is interpreted independently as one of the following types:

The first line of any mtree file must begin with “#mtree”. If a file contains any full path entries, the first line should begin with “#mtree v2.0”, otherwise, the first line should begin with “#mtree v1.0”.
Blank lines are ignored.
Lines beginning with # are ignored.
Lines beginning with / are special commands that influence the interpretation of later lines.
If the first whitespace-delimited word has no / characters, it is the name of a file in the current directory. Any relative entry that describes a directory changes the current directory.
As a special case, a relative entry with the filename .. changes the current directory to the parent directory. Options on dot-dot entries are always ignored.
If the first whitespace-delimited word has a / character after the first character, it is the pathname of a file relative to the starting directory. There can be multiple full entries describing the same file.

Some tools that process mtree files may require that multiple lines describing the same file occur consecutively. It is not permitted for the same file to be mentioned using both a relative and a full file specification.

Special commands

Two special commands are currently defined:

This command defines default values for one or more keywords. It is followed on the same line by one or more whitespace-separated keyword definitions. These definitions apply to all following files that do not specify a value for that keyword.
This command removes any default value set by a previous /set command. It is followed on the same line by one or more keywords separated by whitespace.


After the filename, a full or relative entry consists of zero or more whitespace-separated keyword definitions. Each such definitions consists of a key from the following list immediately followed by an '=' sign and a value. Software programs reading mtree files should warn about unrecognized keywords.

Currently supported keywords are as follows:

The checksum of the file using the default algorithm specified by the cksum(1) utility.
The full pathname of a file whose contents should be compared to the contents of this file.
The file flags as a symbolic name. See chflags(1) for information on these names. If no flags are to be set the string “none” may be used to override the current default.
Ignore any file hierarchy below this file.
The file group as a numeric value.
The file group as a symbolic name.
The MD5 message digest of the file.
A synonym for md5.
The FIPS 160-1 (“SHA-1”) message digest of the file.
A synonym for sha1.
The FIPS 180-2 (“SHA-256”) message digest of the file.
A synonym for sha256.
The RIPEMD160 message digest of the file.
A synonym for ripemd160digest.
A synonym for ripemd160digest.
The current file's permissions as a numeric (octal) or symbolic value.
The number of hard links the file is expected to have.
Make sure this file or directory exists but otherwise ignore all attributes.
The file owner as a numeric value.
The file owner as a symbolic name.
The size, in bytes, of the file.
The file the symbolic link is expected to reference.
The last modification time of the file, in seconds and nanoseconds. The value should include a period character and exactly nine digits after the period.
The type of the file; may be set to any one of the following:

block special device
character special device
regular file
symbolic link


cksum(1), find(1), mtree(8)

mtree-port: Utility for creating and verifying file hierarchies,


The FreeBSD implementation of mtree does not currently support the mtree 2.0 format. The requirement for a “#mtree” signature line is new and not yet widely implemented.


The mtree utility appeared in 4.3BSD-Reno. The MD5 digest capability was added in FreeBSD 2.1, in response to the widespread use of programs which can spoof cksum(1). The SHA-1 and RIPEMD160 digests were added in FreeBSD 4.0, as new attacks have demonstrated weaknesses in MD5. The SHA-256 digest was added in FreeBSD 6.0. Support for file flags was added in FreeBSD 4.0, and mostly comes from NetBSD. The “full” entry format was added by NetBSD.

mtree was ported to Linux by Archie L. Cobbs ⟨⟩

December 31, 2007 Linux 5.14.21-150500.55.52-default