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:

Signature

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

Blank lines are ignored.

Comment

Lines beginning with # are ignored.

Special

Lines beginning with / are special commands that influence the interpretation of later lines.

Relative

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.

dot-dot

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.

Full

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:

/set

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.

/unset

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.

Keywords¶

After the filename, a full or relative entry consists of zero or more whitespace-separated keyword definitions. Each such definition 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:

cksum

The checksum of the file using the default algorithm specified by the cksum(1) utility.

contents

The full pathname of a file that holds the contents of this file.

flags

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.

gid

The file group as a numeric value.

gname

The file group as a symbolic name.

ignore

Ignore any file hierarchy below this file.

link

The target of the symbolic link when type=link.

md5

The MD5 message digest of the file.

md5digest

A synonym for md5.

mode

The current file's permissions as a numeric (octal) or symbolic value.

nlink

The number of hard links the file is expected to have.

nochange

Make sure this file or directory exists but otherwise ignore all attributes.

ripemd160digest

The RIPEMD160 message digest of the file.

rmd160

A synonym for ripemd160digest.

rmd160digest

A synonym for ripemd160digest.

sha1

The FIPS 160-1 (“SHA-1”) message digest of the file.

sha1digest

A synonym for sha1.

sha256

The FIPS 180-2 (“SHA-256”) message digest of the file.

sha256digest

A synonym for sha256.

size

The size, in bytes, of the file.

time

The last modification time of the file.

type

The type of the file; may be set to any one of the following:

block

block special device

char

character special device

dir

directory

fifo

fifo

file

regular file

link

symbolic link

socket

socket

uid

The file owner as a numeric value.

uname

The file owner as a symbolic name.