NAME

man - 格式化手冊頁的宏  

總覽 SYNOPSIS

groff -Tascii -man file ...

groff -Tps -man file ...

man [section] title  

描述 DESCRIPTION

此手冊頁解釋了 groff tmac.man 宏包 (通常叫做 man 宏包) 以及相關的創建手冊頁的慣例。開發者可以使用這個宏包來為 linux 書寫或移植手冊文檔。它與其他版本的這個宏包一般是兼容的，因此移植不是一個大問題 (但是 NET-2 BSD 發布中使用了一個完全不同的宏包叫做 mdoc，參見 mdoc(7)).

注意 NET-2 BSD mdoc 手冊頁也可以使用 groff 處理，只要指定 -mdoc 選項而不是 -man 選項。推薦使用 -mandoc 選項，因為這樣會自動判斷應當使用哪一個。  

導言 PREAMBLE

一篇手冊頁的第一個命令 (注釋行之后) 應當是

.TH title section date source manual,

這里：

title

手冊頁的標題 (例如， MAN).

section

手冊頁的章節號應當放在這里 (例如， 7).

date

最后修改日期 -- 記住要在每次修改過此手冊頁之后修改它，這樣可以方便地進行版本控制

source

命令的來源

對于二進制文件，使用這樣的表述： GNU, NET-2, SLS Distribution, MCC Distribution.

對于系統調用，使用它適用的內核版本來表述： Linux 0.99.11.

對于庫調用，使用函數的來源來表述： GNU, BSD 4.3, Linux DLL 4.4.1.

manual

手冊的標題 (例如： Linux Programmer's Manual).

注意 BSD mdoc 格式的手冊頁以 Dd 命令開始，而不是 TH 命令

手冊章節傳統上如下定義：

1 Commands

用戶可從 shell 運行的命令

2 System calls

必須由內核完成的功能

3 Library calls

大多數 libc 函數，例如 qsort(3))

4 Special files

/dev) 目錄中的文件

5 File formats and conventions

/etc/passwd 等人類可讀的文件的格式說明

6 Games

7 Macro packages and conventions

文件系統標準描述，網絡協議，ASCII 和其他字符集，還有你眼前這份文檔以及其他東西

8 System management commands

類似 mount(8) 等命令，大部分只能由 root 執行

9 Kernel routines

這是廢棄的章節。原來曾想把一些關于核心的文件放在這里，但是實際上只有極少數可以寫成文件放在這里，而且它們也很快過時了。核心開發者可以找到其他更好的資源。

段 SECTIONS

段以 .SH 開始，后跟標題名。如果標題包含空格并且和 .SH 在同一行，則需在標題上加雙引號。傳統的或建議的標題包括： NAME, 總覽 SYNOPSIS, 描述 DESCRIPTION, 返回值 RETURN VALUE, 退出狀態 EXIT STATUS, 錯誤處理 ERROR HANDLING, 錯誤 ERRORS, 選項 OPTIONS, 用法 USAGE, 示例 EXAMPLES, 文件 FILES, 環境 ENVIRONMENT, 診斷 DIAGNOSTICS, 安全 SECURITY, 遵循 CONFORMING TO, 注意 NOTES, BUGS, 作者 AUTHOR, 和 參見 SEE ALSO. 在適合使用約定標題的地方，請使用它；這樣做可以使文章更易讀、易懂。不過，只要您的標題能夠增加易懂性，請放心使用。唯一必須的標題是 NAME, 他應是手冊頁的第一段，后面應緊跟對該命令的簡單描述。比如：

.SH NAME
chess \- the game of chess

請一定要按照這個格式來寫，注意在短橫線 (dash `-') 前要有個斜杠 (slash `'). 這種語法結構在 makewhatis(8) 程序為 whatis(1) 和 apropos(1) 命令建立簡短命令描述時要用到。

其他約定段的內容應為：

總覽 SYNOPSIS

簡要描述命令或函數接口。對命令，顯示他的命令和參數（包括各種選項）；黑體表示各種參數，下劃線（或斜體字）表示可以替換的選項；方括號[]中的是可選項，豎線 | 用于把幾個選項間隔開，小括號()中的部分可以自動重復。對函數，顯示需要的數據聲明或需 #include 包含的項目，后跟函數聲明。

描述 DESCRIPTION

解釋命令、函數或格式的用途。說明其如何與文件及標準輸入交互，他們的標準輸出及標準錯誤。必須要指明的細節。描述一般情況。選項和參數信息放在 OPTIONS（選項）段。如果有語法說明和一些復雜的設定，建議把它們放到 USAGE（用法）段（本段中最好只寫一個概要）。

返回值 RETURN VALUE

列出程序或函數會返回的值，指出引發返回值的條件或原因。

退出狀態 EXIT STATUS

列出可能的退出狀態的值，指出引起返回的程序或原因。

選項 OPTIONS

指出程序可用的選項，及其作用。

用法 USAGE

描述程序的較高級的使用方法。

示例 EXAMPLES

provides one or more examples describing how this function, file or command is used.

文件 FILES

列出程序或函數使用到的文件，比如配置文件、啟動文件和程序直接操作的文件。給出文件的絕對路徑，使用安裝程序調整這些路徑以使其與用戶的實際情況相符。對大多數程序來說，缺省的安裝路徑是 /usr/local，所以你的文件要與此一致。

環境 ENVIRONMENT

列出影響你的程序的所有環境變量，并說明影響的原因。

診斷 DIAGNOSTICS

寫出常會出現的錯誤概述，并說明解決的辦法。你無需解釋系統錯誤信息或信號，除非它們會影響到您的程序。

安全 SECURITY

討論安全問題和相關話題。對應予避免的配置和環境，可能有安全隱患的命令等等給出警告，特別是當它們不是很明顯時。單獨用一段來討論安全并不必要；如果比較好理解的話，把它放在其他段中（比如 描述 或 用法 段）。但是，最好加上它。

遵循 CONFORMING TO

描述它實現的任何標準或約定

注意 NOTES

提供雜項注意事項

BUGS

列出局限、已知的缺點或不便之處，還有其他可能存在的問題。

作者 AUTHOR

列出程序或文件作者，聯系辦法等。

參見 SEE ALSO

以字母順序列出相關的手冊頁（man pages)。通常來講，這是一個手冊頁的最后一段。

字體 FONTS

雖然在 UNIX 世界中有各種對手冊頁（man pages)的不同約定，但在 linux 系統下存在一個字體的標準：

對函數，其參數通常用下劃線（或斜體）， 在總覽（SYNOPSIS)中也是這樣 ，其他部分用黑體。例如

int myfunction(int argc, char **argv);

文件名用下劃線（或斜體），例如，.IR "/usr/include/stdio.h" ), 但在總覽（SYNOPSIS)中，包含的文件用黑體，例如 #include <stdio.h>).

專用宏，一般大寫表示，用黑體（如： MAXINT).

列舉錯誤代號時，代號用黑體（這種列舉通常使用 .TP 宏命令）。

對其他手冊頁的引用（或本頁中某主體的引用）用黑體。手冊章節號用普通體（如： man(7)). 設置字體的宏命令如下：

.B

黑體

.BI

黑體和下劃線（或斜體）交替（描述函數時非常有用）

.BR

黑體和普通體交替（描述引用時非常有用）

.I

下劃線（或斜體）

.IB

下劃線（或斜體）和黑體交替

.IR

普通體和下劃線（或斜體）交替

.RB

普通體和下劃線（或斜體）交替

.RI

小號字和黑體交替

.SB

小號字和黑體交替

.SM

小號字（用于縮寫）

按照慣例，每個命令最多可以有六個小節的參數，但是 GNU 去除了這個限制。小節之間以空格隔開。如果某小節含有空格，則需要給其加上雙引號。各小節在顯示時無間隔，所以 .BR 命令可以指定一個黑體的詞，后跟一個普通體的標點。如果命令后無參數，則命令作用于下一行。  

其他宏命令和字符串 OTHER MACROS AND STRINGS

下面是其他一些相關的宏和預定義的字符串。除非指明，否則所有的宏在本行文本結束時終止。多數宏使用“流行縮進”（prevailing indent)方式。 “流行縮進”的值由緊跟著宏命令的 i 值指定，如果不指定，那就會使用當前的“流行縮進”值。這樣，連續的縮進段就可使用相同的縮進值而不需要重新指定。普通段（不縮進）將“流行縮進”值重值為缺省值（0.5 英寸）。缺省時，縮進是有規則的 en(s)：用 en(s) 或者 em(s) 作為縮進的單位，因為它們會自動地調整字體的大小。 (注：度量距離有不同的單位，當請求需要用到不同的距離時，可以使用默認類型來修飾數字，度量單位是英寸，厘米，pica,en,em,點，unit和垂直行距。 1pica等于1/6英寸，1em等于字母m的寬度，默認寬度取決于troff中使用的字體。En是em的一半。) 其他宏命令定義如下：  

普通段（無縮進） Normal Paragraphs

.LP

與 .PP 相同（開始一個新段）

.P

與 .PP 相同（開始一個新段）

.PP

開始一個新段，重置“流行縮進”值。

相對縮進 Relative Margin Indent

.RS i

開始相對縮進 -- 把左邊界右移 i
 (如果不指定  i 值，則使用“流行縮進”值 ）。同時設定“流行縮進”值為 0.5 英寸。直到使用 .RE 結束這些設定。

.RE

結束相對縮進同時把“流行縮進”恢復原值。

縮進 Indented Paragraph Macros

.HP i

開始懸掛式縮進（段的第一行從左邊揭開時，其余縮進顯示）

.IP x i

在段上標簽 x 。如果不指定 x ，則整個段縮進 i 。如果指定了 x ，則 x 之前的段不縮進，之后的段縮進（有些象 .TP ，不過 x 是跟在命令后面而不是在下一行）。如果 x 太長，后面的文本會挪到下一行（文本不會丟 失或割斷）。

做公告列表，可以用 \(bu (bullet) 或 \(em (em dash). 要用數字或字母列表, 可以用.IP 1. 或 .IP A. 這樣轉換成其他 格式就簡單了。

.TP i

在段上懸掛標簽。標簽在下一行指定，但是結果和 .IP 相像。

超文本鏈接宏 Hypertext Link Macros

.UR u

建立一個超文本鏈接到 URI (URL) u; 并以 UE 結束。當轉換為 HTML 格式時，他會轉換為 <A HREF="u">. 有個例外：如果 u 是特殊字符 “ ：”，則之后不能建立任何超級鏈接，直到以 UE 結束（這用來在不需要超級鏈接時禁止他）。 LALR(1) 這個宏比較新，很多程序可能并不對他進行處理。但是由于很多工具 (包括 troff) 簡單地忽略未定義宏 (或者最壞的將它們插入到文本中), 插入它們是安全的

.UE

結束相應的 UR 超級鏈接。轉換為HTML后是 </A>.

.UN u

給超級聯接指定名稱為 u; 不需要以 UE UE 結束。轉換為 HTML 后為： <A NAME="u" id="u">&nbsp;</A> (the &nbsp; is optional if support for Mosaic is unneeded).

雜項宏 Miscellaneous Macros

.DT

重置 tab 值為缺省(每一個0.5英寸)。不引起中斷。

.IX ...

插入索引信息（方便搜索系統工作，或打印索引列表）。在頁中索引信息不能正常顯示。如果只有一個參數，參數作為獨立的索引項指向手冊頁的內容。如果有兩個參數，他可能是 Perl 手冊頁格式；第一個參數指定類型名（命令名，標題 ，題頭，子段貨源素之一），第二個參數指明自己的索引名。另外，長索引形式：每個參數是一個索引項，次級索引項，再次級索引項，等等直到以空參數結束，然后是程序名參數，\m，還有一小段描述。還可能在跟上一個空參數，有可能是頁控制信息（如： PAGE START)。舉例如下： "programmingtools""make""""make--- build programs".

.PD d

在段中間垂直距離空開 d (如果不指定，則缺省為 d=0.4v)，不引起中斷。

.SS t

子標題 t 象是 .SH, 但是作為段中的字標題使用）

預定義字符串 Predefined Strings

man 預定義了下列字符串

\*R

注冊符號: ®

\*S

改變成缺省字體大小

\*(Tm

商標符號:

\*(lq

左雙引號: ``

\*(rq

右雙引號: ''

安全子集 SAFE SUBSET

理論上 man 是一個 troff 宏命令包，實際上很多工具程序沒有支持所有的 man 宏命令。因此，為了這些程序可以正常工作最好忽略 troff 的一些比較另類的宏。避免使用各種不同的 troff 預處理程序（如果必須的話，用 tbl(1) 吧，但是在建立雙列表時請使用 IP 和 TP 命令）。避免使用計算；大多數其他程序不能處理他。使用簡單的命令比較容易轉換為其他格式。下面的宏命令一般認為是安全的（雖然多數時候他們都被忽略了）： \ , ., ad, bp, br, ce, de, ds, el, ie, if, fi, ft, hy, ig, in, na, ne, nf, nh, ps, so, sp, ti, tr.

你還可能使用 troff 轉義字符（這些轉移符號以 \ 開始）。但你要在文本中顯示反斜線時，用\e。其他轉義字符包括： \', \`, \-, \., \ , \%, \*x, \*(xx, \(xx, \$N, \nx, \n(xx, \fx, 和 \f(xx. 其中 x、xx 是任意字符，N 是任意數字不要使用轉義字符來畫圖。

不要隨意使用 bp （break page(中斷頁））。 sp （vertical space(垂直距離）只應使用正值。不要用 (de) （define（定義）定義與現有的宏同名的宏（無論 man 或 mdoc)；這種重新定義可能會被忽略。每個正縮進 (in) 應對應一個負縮進（即使在使用 RS 和 RE 是也不例外）。 The condition test (if,ie) should only have 't' or 'n' as the condition. 可以使用的只有可忽略的轉換 (tr). 改變字體命令 (ft 和 \f 轉義序列) 只能帶如下參數： 1, 2, 3, 4, R, I, B, P, or CW (ft 命令也可以不帶參數)。

如果你是用更多的功能，用各種程序仔細察看一下結果。如果你肯定某功能是安全的，請告訴我們，以便把他增加到這個列表中。  

注意 NOTES

盡量在文本中包含完整的 URL（或URIs）；一些工具軟件（如： man2html(1) ）能夠自動把它們轉換為超級鏈接。您也可用 UR 命令指定鏈接到相關信息。輸入完整的 URL(如：<http://www.kernel-notes.org> )。

Tools processing these files should open the file and examine the first non-whitespace character. 以(.)或（')開始一行，表明是基于 troff 的文件（如： man 或 mdoc)。如果是（<）表明基于 SGML/XML (如：HTML 或 Docbook)．其他可能是純文本。(例如 "catman" 的結果)

有些 man 以'\"和空格再加字符列開始，表示他的預處理方法。為了 troff 翻譯器程序處理起來簡單一些，您僅應使用 tbl(1), 而不是其他什么東東，Linux 可以檢測到這一點。不過，你或許想要包含這些信息以使其可以在其他系統得到處理。下面是預處理調用的定義：

e

eqn(1)

g

grap(1)

p

pic(1)

r

refer(1)

t

tbl(1)

v

vgrind(1)

文件 FILES

/usr/share/groff/[*/]tmac/tmac.an
/usr/man/whatis  

BUGS

大多數宏命令描述的是格式（比如：字體和空格）而不是內容描述（比如： 這段文字指向另外一頁），與 mdoc 和 DocBook 正好相反（HTML 也有比較多的內容描述）。這使得 man 難以轉換為其他形式，不容易與其他文件組合或自動插入交叉引用。遵照以上的安全說明，就比較容易在將來把他轉換為其他格式。

The Sun macro TX 下不能用。  

作者 AUTHORS

---

James Clark (jjc@jclark.com) wrote the implementation of the macro package.

---

Rickard E. Faith (faith@cs.unc.edu) wrote the initial version of this manual page.

---

Jens Schweikhardt (schweikh@noc.fdn.de) wrote the Linux Man-Page Mini-HOWTO (which influenced this manual page).

---

David A. Wheeler (dwheeler@ida.org) heavily modified this manual page, such as adding detailed information on sections and macros.

參見 SEE ALSO

apropos(1), groff(1), man(1), man2html(1), mdoc(7), mdoc.samples(7), whatis(1)

#p#

NAME

man - macros to format man pages  

SYNOPSIS

groff -Tascii -man file ...

groff -Tps -man file ...

man [section] title  

DESCRIPTION

This manual page explains the groff tmac.an macro package (often called the man macro package) and related conventions for creating manual (man) pages. This macro package should be used by developers when writing or porting man pages for Linux. It is fairly compatible with other versions of this macro package, so porting man pages should not be a major problem (exceptions include the NET-2 BSD release, which uses a totally different macro package called mdoc; see mdoc(7)).

Note that NET-2 BSD mdoc man pages can be used with groff simply by specifying the -mdoc option instead of the -man option. Using the -mandoc option is, however, recommended, since this will automatically detect which macro package is in use.  

PREAMBLE

The first command in a man page (after comment lines) should be

.TH title section date source manual,

where:

title

The title of the man page (e.g., MAN).

section

The section number the man page should be placed in (e.g., 7).

date

The date of the last revision---remember to change this every time a change is made to the man page, since this is the most general way of doing version control.

source

The source of the command.

For binaries, use something like: GNU, NET-2, SLS Distribution, MCC Distribution.

For system calls, use the version of the kernel that you are currently looking at: Linux 0.99.11.

For library calls, use the source of the function: GNU, BSD 4.3, Linux DLL 4.4.1.

manual

The title of the manual (e.g., Linux Programmer's Manual).

Note that BSD mdoc-formatted pages begin with the Dd command, not the TH command.

The manual sections are traditionally defined as follows:

1 Commands

Those commands that can be executed by the user from within a shell.

2 System calls

Those functions which must be performed by the kernel.

3 Library calls

Most of the libc functions, such as qsort(3).

4 Special files

Files found in /dev.

5 File formats and conventions

The format for /etc/passwd and other human-readable files.

6 Games

7 Conventions and miscellaneous

A description of the standard file system layout, network protocols, ASCII and other character codes, this man page, and other things.

8 System management commands

Commands like mount(8), many of which only root can execute.

9 Kernel routines

This is an obsolete manual section. Once it was thought a good idea to document the Linux kernel here, but in fact very little has been documented, and the documentation that exists is outdated already. There are better sources of information for kernel developers.

SECTIONS

Sections are started with .SH followed by the heading name. If the name contains spaces and appears on the same line as .SH, then place the heading in double quotes. Traditional or suggested headings include: NAME, SYNOPSIS, DESCRIPTION, RETURN VALUE, EXIT STATUS, ERROR HANDLING, ERRORS, OPTIONS, USAGE, EXAMPLES, FILES, ENVIRONMENT, DIAGNOSTICS, SECURITY, CONFORMING TO, NOTES, BUGS, AUTHOR, and SEE ALSO. Where a traditional heading would apply, please use it; this kind of consistency can make the information easier to understand. However, feel free to create your own headings if they make things easier to understand. The only required heading is NAME, which should be the first section and be followed on the next line by a one line description of the program:

.SH NAME
chess \- the game of chess

It is extremely important that this format is followed, and that there is a backslash before the single dash which follows the command name. This syntax is used by the makewhatis(8) program to create a database of short command descriptions for the whatis(1) and apropos(1) commands.

Some other traditional sections have the following contents:

SYNOPSIS

briefly describes the command or function's interface. For commands, this shows the syntax of the command and its arguments (including options); boldface is used for as-is text and italics are used to indicate replaceable arguments. Brackets ([]) surround optional arguments, vertical bars (|) separate choices, and ellipses (...) can be repeated. For functions, it shows any required data declarations or #include directives, followed by the function declaration.

DESCRIPTION

gives an explanation of what the command, function, or format does. Discuss how it interacts with files and standard input, and what it produces on standard output or standard error. Omit internals and implementation details unless they're critical for understanding the interface. Describe the usual case; for information on options use the OPTIONS section. If there is some kind of input grammar or complex set of subcommands, consider describing them in a separate USAGE section (and just place an overview in the DESCRIPTION section).

RETURN VALUE

gives a list of the values the library routine will return to the caller and the conditions that cause these values to be returned.

EXIT STATUS

lists the possible exit status values or a program and the conditions that cause these values to be returned.

OPTIONS

describes the options accepted by the program and how they change its behavior.

USAGE

describes the grammar of any sublanguage this implements.

EXAMPLES

provides one or more examples describing how this function, file or command is used.

FILES

lists the files the program or function uses, such as configuration files, startup files, and files the program directly operates on. Give the full pathname of these files, and use the installation process to modify the directory part to match user preferences. For many programs, the default installation location is in /usr/local, so your base manual page should use /usr/local as the base.

ENVIRONMENT

lists all environment variables that affect your program or function and how they affect it.

DIAGNOSTICS

gives an overview of the most common error messages and how to cope with them. You don't need to explain system error messages or fatal signals that can appear during execution of any program unless they're special in some way to your program.

SECURITY

discusses security issues and implications. Warn about configurations or environments that should be avoided, commands that may have security implications, and so on, especially if they aren't obvious. Discussing security in a separate section isn't necessary; if it's easier to understand, place security information in the other sections (such as the DESCRIPTION or USAGE section). However, please include security information somewhere!

CONFORMING TO

describes any standards or conventions this implements.

NOTES

provides miscellaneous notes.

BUGS

lists limitations, known defects or inconveniences, and other questionable activities.

AUTHOR

lists authors of the documentation or program so you can mail in bug reports.

SEE ALSO

lists related man pages in alphabetical order, possibly followed by other related pages or documents. Conventionally this is the last section.

FONTS

Although there are many arbitrary conventions for man pages in the UNIX world, the existence of several hundred Linux-specific man pages defines our font standards:

For functions, the arguments are always specified using italics, even in the SYNOPSIS section, where the rest of the function is specified in bold:

int myfunction(int argc, char **argv);

Filenames are always in italics (e.g., /usr/include/stdio.h), except in the SYNOPSIS section, where included files are in bold (e.g., #include <stdio.h>).

Special macros, which are usually in upper case, are in bold (e.g., MAXINT).

When enumerating a list of error codes, the codes are in bold (this list usually uses the .TP macro).

Any reference to another man page (or to the subject of the current man page) is in bold. If the manual section number is given, it is given in Roman (normal) font, without any spaces (e.g., man(7)).

The commands to select the type face are:

.B

Bold

.BI

Bold alternating with italics (especially useful for function specifications)

.BR

Bold alternating with Roman (especially useful for referring to other manual pages)

.I

Italics

.IB

Italics alternating with bold

.IR

Italics alternating with Roman

.RB

Roman alternating with bold

.RI

Roman alternating with italics

.SB

Small alternating with bold

.SM

Small (useful for acronyms)

Traditionally, each command can have up to six arguments, but the GNU implementation removes this limitation (you might still want to limit yourself to 6 arguments for portability's sake). Arguments are delimited by spaces. Double quotes can be used to specify an argument which contains spaces. All of the arguments will be printed next to each other without intervening spaces, so that the .BR command can be used to specify a word in bold followed by a mark of punctuation in Roman. If no arguments are given, the command is applied to the following line of text.  

OTHER MACROS AND STRINGS

Below are other relevant macros and predefined strings. Unless noted otherwise, all macros cause a break (end the current line of text). Many of these macros set or use the "prevailing indent." The "prevailing indent" value is set by any macro with the parameter i below; macros may omit i in which case the current prevailing indent will be used. As a result, successive indented paragraphs can use the same indent without re-specifying the indent value. A normal (non-indented) paragraph resets the prevailing indent value to its default value (0.5 inches). By default a given indent is measured in ens; try to ens or ems as units for indents, since these will automatically adjust to font size changes. The other key macro definitions are:  

Normal Paragraphs

.LP

Same as .PP (begin a new paragraph).

.P

Same as .PP (begin a new paragraph).

.PP

Begin a new paragraph and reset prevailing indent.

Relative Margin Indent

.RS i

Start relative margin indent - moves the left margin i to the right (if i is omitted, the prevailing indent value is used). A new prevailing indent is set to 0.5 inches. As a result, all following paragraph(s) will be indented until the corresponding .RE.

.RE

End relative margin indent and restores the previous value of the prevailing indent.

Indented Paragraph Macros

.HP i

Begin paragraph with a hanging indent (the first line of the paragraph is at the left margin of normal paragraphs, and the rest of the paragraph's lines are indented).

.IP x i

Indented paragraph with optional hanging tag. If the tag x is omitted, the entire following paragraph is indented by i. If the tag x is provided, it is hung at the left margin before the following indented paragraph (this is just like .TP except the tag is included with the command instead of being on the following line). If the tag is too long, the text after the tag will be moved down to the next line (text will not be lost or garbled). For bulleted lists, use this macro with \(bu (bullet) or \(em (em dash) as the tag, and for numbered lists, use the number or letter followed by a period as the tag; this simplifies translation to other formats.

.TP i

Begin paragraph with hanging tag. The tag is given on the next line, but its results are like those of the .IP command.

Hypertext Link Macros

.UR u

Begins a hypertext link to the URI (URL) u; it will end with the corresponding UE command. When generating HTML this should translate into the HTML command <A HREF="u">. There is an exception: if u is the special value ":", then no hypertext link of any kind will be generated until after the closing UE (this permits disabling hypertext links in phrases like LALR(1) when linking is not appropriate). These hypertext link "macros" are new, and many tools won't do anything with them, but since many tools (including troff) will simply ignore undefined macros (or at worst insert their text) these are safe to insert.

.UE

Ends the corresponding UR command; when generating HTML this should translate into </A>.

.UN u

Creates a named hypertext location named u; do not include a corresponding UE command. When generating HTML this should translate into the HTML command <A NAME="u" id="u">&nbsp;</A> (the &nbsp; is optional if support for Mosaic is unneeded).

Miscellaneous Macros

.DT

Reset tabs to default tab values (every 0.5 inches); does not cause a break.

.PD d

Set inter-paragraph vertical distance to d (if omitted, d=0.4v); does not cause a break.

.SS t

Subheading t (like .SH, but used for a subsection inside a section).

Predefined Strings

The man package has the following predefined strings:

\*R

Registration Symbol: ®

\*S

Change to default font size

\*(Tm

Trademark Symbol:

\*(lq

Left angled doublequote: ``

\*(rq

Right angled doublequote: ''

SAFE SUBSET

Although technically man is a troff macro package, in reality a large number of other tools process man page files that don't implement all of troff's abilities. Thus, it's best to avoid some of troff's more exotic abilities where possible to permit these other tools to work correctly. Avoid using the various troff preprocessors (if you must, go ahead and use tbl(1), but try to use the IP and TP commands instead for two-column tables). Avoid using computations; most other tools can't process them. Use simple commands that are easy to translate to other formats. The following troff macros are believed to be safe (though in many cases they will be ignored by translators): \ , ., ad, bp, br, ce, de, ds, el, ie, if, fi, ft, hy, ig, in, na, ne, nf, nh, ps, so, sp, ti, tr.

You may also use many troff escape sequences (those sequences beginning with \). When you need to include the backslash character as normal text, use \e. Other sequences you may use, where x or xx are any characters and N is any digit, include: \', \`, \-, \., \ , \%, \*x, \*(xx, \(xx, \$N, \nx, \n(xx, \fx, and \f(xx. Avoid using the escape sequences for drawing graphics.

Do not use the optional parameter for bp (break page). Use only positive values for sp (vertical space). Don't define a macro (de) with the same name as a macro in this or the mdoc macro package with a different meaning; it's likely that such redefinitions will be ignored. Every positive indent (in) should be paired with a matching negative indent (although you should be using the RS and RE macros instead). The condition test (if,ie) should only have 't' or 'n' as the condition. Only translations (tr) that can be ignored should be used. Font changes (ft and the \f escape sequence) should only have the values 1, 2, 3, 4, R, I, B, P, or CW (the ft command may also have no parameters).

If you use capabilities beyond these, check the results carefully on several tools. Once you've confirmed that the additional capability is safe, let the maintainer of this document know about the safe command or sequence that should be added to this list.  

NOTES

By all means include full URLs (or URIs) in the text itself; some tools such as man2html(1) can automatically turn them into hypertext links. You can also use the new UR macro to identify links to related information. If you include URLs, use the full URL (e.g., <http://www.kernelnotes.org>) to ensure that tools can automatically find the URLs.

Tools processing these files should open the file and examine the first non-whitespace character. A period (.) or single quote (') at the beginning of a line indicates a troff-based file (such as man or mdoc). A left angle bracket (<) indicates an SGML/XML-based file (such as HTML or Docbook). Anything else suggests simple ASCII text (e.g., a "catman" result).

Many man pages begin with '\" followed by a space and a list of characters, indicating how the page is to be preprocessed. For portability's sake to non-troff translators we recommend that you avoid using anything other than tbl(1), and Linux can detect that automatically. However, you might want to include this information so your man page can be handled by other (less capable) systems. Here are the definitions of the preprocessors invoked by these characters:

e

eqn(1)

g

grap(1)

p

pic(1)

r

refer(1)

t

tbl(1)

v

vgrind(1)

FILES

/usr/share/groff/[*/]tmac/tmac.an
/usr/man/whatis  

BUGS

Most of the macros describe formatting (e.g., font type and spacing) instead of marking semantic content (e.g., this text is a reference to another page), compared to formats like mdoc and DocBook (even HTML has more semantic markings). This situation makes it harder to vary the man format for different media, to make the formatting consistent for a given media, and to automatically insert cross-references. By sticking to the safe subset described above, it should be easier to automate transitioning to a different reference page format in the future.

The Sun macro TX is not implemented.  

AUTHORS

---

James Clark (jjc@jclark.com) wrote the implementation of the macro package.

---

Rickard E. Faith (faith@cs.unc.edu) wrote the initial version of this manual page.

---

Jens Schweikhardt (schweikh@noc.fdn.de) wrote the Linux Man-Page Mini-HOWTO (which influenced this manual page).

---

David A. Wheeler (dwheeler@ida.org) heavily modified this manual page, such as adding detailed information on sections and macros.

SEE ALSO

apropos(1), groff(1), man(1), man2html(1), mdoc(7), mdoc.samples(7), whatis(1)