man8 : System administration Programs used by system administrators for system operation and maintenance are documented here. Some of these programs are also occasionally useful for normal users.

man7 : Miscellaneous Manual pages that are difficult to classify are designated as being section 7. The troff and other text processing macro packages are found here.

man6 : Games This chapter documents games, demos, and generally trivial programs. Different people have various notions about how essential this is.

man5 : File formats The formats for many data files are documented in the section 5. This includes various include files, program output files, and system files.

man4 : Special files Section 4 describes the special files, related driver functions, and networking support available in the system. Typically, this includes the device files found in /dev and the kernel interface to networking protocol support.

man3 : Library functions and subroutines Section 3 describes program library routines that are not direct calls to kernel services. This and chapter 2 are only really of interest to programmers.

man2 : System calls This section describes all of the system calls (requests for the kernel to perform operations).

man1 : User programs Manual pages that describe publicly accessible commands are contained in this chapter. Most program documentation that a user will need to use is located here.

Manual pages are stored in <mandir>/<locale>/man<section>/<arch> . An explanation of <mandir> , <locale> , <section> , and <arch> is given below.

The primary <mandir> of the system is /usr/share/man . /usr/share/man contains manual information for commands and data under the / and /usr filesystems.

This section details the organization for manual pages throughout the system, including /usr/share/man . Also refer to the section on /var/cache/man .

The following directories, or symbolic links to directories, must be in /usr/share/<mandir>/<locale> , unless they are empty:

Directory Description man1 User programs (optional) man2 System calls (optional) man3 Library calls (optional) man4 Special files (optional) man5 File formats (optional) man6 Games (optional) man7 Miscellaneous (optional) man8 System administration (optional)

The component <section> describes the manual section.

Provisions must be made in the structure of /usr/share/man to support manual pages which are written in different (or multiple) languages. These provisions must take into account the storage and reference of these manual pages. Relevant factors include language (including geographical-based differences), and character code set.

This naming of language subdirectories of /usr/share/man is based on Appendix E of the POSIX 1003.1 standard which describes the locale identification string — the most well-accepted method to describe a cultural environment. The <locale> string is:

<language>[_<territory>][.<character-set>][,<version>]

The <language> field must be taken from ISO 639 (a code for the representation of names of languages). It must be two characters wide and specified with lowercase letters only.

The <territory> field must be the two-letter code of ISO 3166 (a specification of representations of countries), if possible. (Most people are familiar with the two-letter codes used for the country codes in email addresses.) It must be two characters wide and specified with uppercase letters only.

The <character-set> field must represent the standard describing the character set. If the ­<character-set> field is just a numeric specification, the number represents the number of the international standard describing the character set. It is recommended that this be a numeric representation if possible (ISO standards, especially), not include additional punctuation symbols, and that any letters be in lowercase.

A parameter specifying a <version> of the profile may be placed after the ­<character-set> field, delimited by a comma. This may be used to discriminate between different cultural needs; for instance, dictionary order versus a more systems-oriented collating order. This standard recommends not using the <version> field, unless it is necessary.

Systems which use a unique language and code set for all manual pages may omit the <locale> substring and store all manual pages in <mandir> . For example, systems which only have English manual pages coded with ASCII, may store manual pages (the man<section> directories) directly in /usr/share/man . (That is the traditional circumstance and arrangement, in fact.)

Countries for which there is a well-accepted standard character code set may omit the ­<character-set> field, but it is strongly recommended that it be included, especially for countries with several competing standards.

Various examples:

Language Territory Character Set Directory English — ASCII /usr/share/man/en English United Kingdom ISO 8859-15 /usr/share/man/en_GB English United States ASCII /usr/share/man/en_US French Canada ISO 8859-1 /usr/share/man/fr_CA French France ISO 8859-1 /usr/share/man/fr_FR German Germany ISO 646 /usr/share/man/de_DE.646 German Germany ISO 6937 /usr/share/man/de_DE.6937 German Germany ISO 8859-1 /usr/share/man/de_DE.88591 German Switzerland ISO 646 /usr/share/man/de_CH.646 Japanese Japan JIS /usr/share/man/ja_JP.jis Japanese Japan SJIS /usr/share/man/ja_JP.sjis Japanese Japan UJIS (or EUC-J) /usr/share/man/ja_JP.ujis

Similarly, provision must be made for manual pages which are architecture-dependent, such as documentation on device-drivers or low-level system administration commands. These must be placed under an <arch> directory in the appropriate man<section> directory; for example, a man page for the i386 ctrlaltdel(8) command might be placed in /usr/share/man/<locale>/man8/i386/ctrlaltdel.8 .

Manual pages for commands and data under /usr/local are stored in /usr/local/man . Manual pages for X11R6 are stored in /usr/X11R6/man . It follows that all manual page hierarchies in the system must have the same structure as /usr/share/man .

The cat page sections ( cat<section> ) containing formatted manual page entries are also found within subdirectories of <mandir>/<locale> , but are not required nor may they be distributed in lieu of nroff source manual pages.

The numbered sections "1" through "8" are traditionally defined. In general, the file name for manual pages located within a particular section end with .<section> .

In addition, some large sets of application-specific manual pages have an additional suffix appended to the manual page filename. For example, the MH mail handling system manual pages must have mh appended to all MH manuals. All X Window System manual pages must have an x appended to the filename.