📄 ch12_04.htm
字号:
<html><head><title>Default Operation of Requests (UNIX in a Nutshell: System V Edition)</title><link rel="stylesheet" type="text/css" href="../style/style1.css" /><meta name="DC.Creator" content="Arnold Robbins" /><meta name="DC.Format" content="text/xml" scheme="MIME" /><meta name="DC.Language" content="en-US" /><meta name="DC.Publisher" content="O'Reilly & Associates, Inc." /><meta name="DC.Source" scheme="ISBN" content="1-56592-427-4" /><meta name="DC.Subject.Keyword" content="stuff" /><meta name="DC.Title" content="UNIX in a Nutshell: System V Edition" /><meta name="DC.Type" content="Text.Monograph" /></head><body bgcolor="#ffffff"><img src="gifs/smbanner.gif" usemap="#banner-map" border="0" alt="Book Home" /><map name="banner-map"><area shape="rect" coords="1,-2,616,66" href="index.htm" alt="Book Title" /><area shape="rect" coords="629,-11,726,25" href="jobjects/fsearch.htm" alt="Search this book" /></map><div class="navbar"><table width="684" border="0"><tr><td align="left" valign="top" width="228"><a href="ch12_03.htm"><img src="../gifs/txtpreva.gif" alt="Previous" border="0" /></a></td><td align="center" valign="top" width="228" /><td align="right" valign="top" width="228"><a href="ch12_05.htm"><img src="../gifs/txtnexta.gif" alt="Next" border="0" /></a></td></tr></table></div><h2 class="sect1">12.4. Default Operation of Requests</h2><p><a name="unut-ch-12-ix-requests-nrofftroff" /><a name="unut-ch-12-ix-commands-nrofftroff-requests" /><a name="unut-ch-12-ix-nroff-program-requests-list-of" /><a name="unut-ch-12-ix-troff-program-requests-list-of" /><tt class="literal">nroff</tt>/<tt class="literal">troff</tt> initializes the formatting environment.<a name="IXT-12-123365" />For example, unless you reset the line length, <tt class="literal">nroff</tt>/<tt class="literal">troff</tt> uses6.5 inches. Most requests can change the default environment, andthose that can are listed in <a href="ch12_04.htm#unut-ch-12-tab-1">Table 12-1</a>.The second column lists the initial or default value in effect before the request is used.If no initial value applies, a hyphen (–) is used.The third column shows the effect if a request's optional argumentis not used. Here, a hyphen is used if the request doesn't accept an argument or if the argument is required.</p><a name="unut-ch-12-tab-1" /><h4 class="objtitle">Table 12-1. Requests That Affect the Default Environment</h4><table border="1" cellpadding="3"><tr><th>Request</th><th><em class="emphasis">Initial Value</em></th><th><em class="emphasis">If No Argument</em></th><th>Description</th></tr><tr><td><tt class="literal">.ad</tt></td><td>Justify</td><td>Justify</td><td><p>Adjust margins.</p></td></tr><tr><td><tt class="literal">.af</tt></td><td>Lowercase arabic</td><td>–</td><td><p>Assign a format to a register.</p></td></tr><tr><td><tt class="literal">.am</tt></td><td>–</td><td>End call with <tt class="literal">..</tt></td><td><p>Append to a macro.</p></td></tr><tr><td><tt class="literal">.bd</tt></td><td>Off</td><td>–</td><td><p>Embolden font.</p></td></tr><tr><td><tt class="literal">.c2</tt></td><td><tt class="literal">'</tt></td><td><tt class="literal">'</tt></td><td><p>Set no-break control character.</p></td></tr><tr><td><tt class="literal">.cc</tt></td><td><tt class="literal">.</tt></td><td><tt class="literal">.</tt></td><td><p>Set control character.</p></td></tr><tr><td><tt class="literal">.ce</tt></td><td>Off</td><td>Center one line</td><td><p>Center lines.</p></td></tr><tr><td><tt class="literal">.ch</tt></td><td>–</td><td>Turn off trap</td><td><p>Change trap position.</p></td></tr><tr><td><tt class="literal">.cs</tt></td><td>Off</td><td>–</td><td><p>Set constant-width spacing.</p></td></tr><tr><td><tt class="literal">.cu</tt></td><td>Off</td><td>One line</td><td><p>Continuous underline/italicize.</p></td></tr><tr><td><tt class="literal">.da</tt></td><td>–</td><td>End the diversion</td><td><p>Divert text and append to a macro.</p></td></tr><tr><td><tt class="literal">.de</tt></td><td>–</td><td>End macro with <tt class="literal">..</tt></td><td><p>Define a macro.</p></td></tr><tr><td><tt class="literal">.di</tt></td><td>–</td><td>End the diversion</td><td><p>Divert text to a macro.</p></td></tr><tr><td><tt class="literal">.dt</tt></td><td>–</td><td>Turn off trap</td><td><p>Set a diversion trap.</p></td></tr><tr><td><tt class="literal">.ec</tt></td><td>\</td><td>\</td><td><p>Set escape character.</p></td></tr><tr><td><tt class="literal">.eo</tt></td><td>On</td><td>–</td><td><p>Turn off escape character.</p></td></tr><tr><td><tt class="literal">.ev</tt></td><td>0</td><td><p>Previous environment</p></td><td><p>Change environment (push down).</p></td></tr><tr><td><tt class="literal">.fc</tt></td><td>Off</td><td>Off</td><td><p>Set field delimiter and pad character.</p></td></tr><tr><td><tt class="literal">.fi</tt></td><td>Fill</td><td>–</td><td><p>Fill lines.</p></td></tr><tr><td><tt class="literal">.fp</tt></td><td><p>1=R</p><p>2=I</p><p>3=B</p><p>4=S</p></td><td>–</td><td><p>Mount font (on positions 1–4).</p></td></tr><tr><td><tt class="literal">.ft</tt></td><td>Roman</td><td>Previous font</td><td><p>Set font.</p></td></tr><tr><td><tt class="literal">.hc</tt></td><td><tt class="literal">\%</tt></td><td><tt class="literal">\%</tt></td><td><p>Set hyphenation character.</p></td></tr><tr><td><tt class="literal">.hy</tt></td><td>Mode 1</td><td>Mode 1</td><td><p>Set hyphenation mode.</p></td></tr><tr><td><tt class="literal">.ig</tt></td><td>–</td><td>End with <tt class="literal">..</tt></td><td><p>Suppress (ignore) text in output.</p></td></tr><tr><td><tt class="literal">.in</tt></td><td>0</td><td>Previous indent</td><td><p>Indent.</p></td></tr><tr><td><tt class="literal">.it</tt></td><td>–</td><td>Turn off trap</td><td><p>Set a trap for input line counting.</p></td></tr><tr><td><tt class="literal">.lc</tt></td><td><tt class="literal">.</tt></td><td>None</td><td><p>Set leader character.</p></td></tr><tr><td><tt class="literal">.lg</tt></td><td><p>Off (<tt class="literal">nroff</tt>)</p><p>On (<tt class="literal">troff</tt>)</p></td><td>On</td><td><p>Ligature mode.</p></td></tr><tr><td><tt class="literal">.ll</tt></td><td>6.5 inches</td><td><p>Previous line length</p></td><td><p>Set line length.</p></td></tr><tr><td><tt class="literal">.ls</tt></td><td>Single-space</td><td>Previous mode</td><td><p>Set line spacing.</p></td></tr><tr><td><tt class="literal">.lt</tt></td><td>6.5 inches</td><td><p>Previous title length</p></td><td><p>Set length of title.</p></td></tr><tr><td><tt class="literal">.mc</tt></td><td>–</td><td>Turn off</td><td><p>Set the margin character.</p></td></tr><tr><td><tt class="literal">.mk</tt></td><td>–</td><td>Internal</td><td><p>Mark vertical position.</p></td></tr><tr><td><tt class="literal">.na</tt></td><td>Adjust</td><td>–</td><td><p>Don't adjust margins.</p></td></tr><tr><td><tt class="literal">.ne</tt></td><td>–</td><td>One vertical line</td><td><p>Keep lines on same page if there's room.</p></td></tr><tr><td><tt class="literal">.nf</tt></td><td>Fill</td><td>–</td><td><p>Don't fill lines.</p></td></tr><tr><td><tt class="literal">.nh</tt></td><td>On</td><td>–</td><td><p>Turn off hyphenation.</p></td></tr><tr><td><tt class="literal">.nm</tt></td><td>Off</td><td>Off</td><td><p>Line-numbering mode.</p></td></tr><tr><td><tt class="literal">.nn</tt></td><td>–</td><td>One line</td><td><p>Don't number next <em class="emphasis">N</em> lines.</p></td></tr><tr><td><tt class="literal">.ns</tt></td><td>Space mode</td><td>–</td><td><p>Enable no-space mode.</p></td></tr><tr><td><tt class="literal">.nx</tt></td><td>–</td><td>End of file</td><td><p>Go to a file.</p></td></tr><tr><td><tt class="literal">.pc</tt></td><td><tt class="literal">%</tt></td><td>Off</td><td><p>Set page character.</p></td></tr><tr><td><tt class="literal">.pl</tt></td><td>11 inches</td><td>11 inches</td><td><p>Set page length.</p></td></tr><tr><td><tt class="literal">.pn</tt></td><td>Page 1</td><td>–</td><td><p>Set page number.</p></td></tr><tr><td><tt class="literal">.po</tt></td><td><p>0 (<tt class="literal">nroff</tt>); 26/27 inch (<tt class="literal">otroff</tt>)</p><p>1 inch (<tt class="literal">ditroff</tt>)</p></td><td>Previous offset</td><td><p>Change page offset.</p></td></tr><tr><td><tt class="literal">.ps</tt></td><td>10</td><td><p>Previous point size</p></td><td><p>Set point size.</p></td></tr><tr><td><tt class="literal">.rd</tt></td><td>–</td><td>Ring bell</td><td><p>Read from the terminal.</p></td></tr><tr><td><tt class="literal">.rt</tt></td><td>–</td><td>Internal</td><td><p>Return to marked vertical place.</p></td></tr><tr><td><tt class="literal">.sp</tt></td><td>–</td><td>One vertical line</td><td><p>Output blank spacing.</p></td></tr><tr><td><tt class="literal">.ss</tt></td><td>12/36 em</td><td>Ignored</td><td><p>Set character spacing.</p></td></tr><tr><td><tt class="literal">.sv</tt></td><td>–</td><td>One vertical line</td><td><p>Save (store) spacing.</p></td></tr><tr><td><tt class="literal">.ta</tt></td><td><p>8 en (<tt class="literal">nroff</tt>); 1/2 inch (<tt class="literal">troff</tt>)</p></td><td>–</td><td><p>Define tab settings.</p></td></tr><tr><td><tt class="literal">.tc</tt></td><td>–</td><td>–</td><td><p>Set tab repetition character.</p></td></tr><tr><td><tt class="literal">.ti</tt></td><td>0</td><td>–</td><td>Indent next line.</td></tr><tr><td><tt class="literal">.tm</tt></td><td>–</td><td>Newline</td><td><p>Print a message, then continue.</p></td></tr><tr><td><tt class="literal">.tr</tt></td><td>–</td><td>–</td><td><p>Translate pairs of characters on output.</p></td></tr><tr><td><tt class="literal">.uf</tt></td><td>Italic</td><td>Italic</td><td><p>Set font for underlining.</p></td></tr><tr><td><tt class="literal">.ul</tt></td><td>0</td><td>One line</td><td>Underline/italicize.</td></tr><tr><td><tt class="literal">.vs</tt></td><td><p>1/6 inch (<tt class="literal">nroff</tt>); 12 points (<tt class="literal">troff</tt>)</p></td><td>Previous value</td><td><p>Set vertical spacing for lines.</p></td></tr></table><p><p>Comments in <tt class="literal">nroff</tt>/<tt class="literal">troff</tt> begin with <tt class="literal">\"</tt>.Lines beginning with <tt class="literal">.</tt> that contain an unknown requestare ignored. In general, don't put leading whitespace on your text lines.This causes a break, and <tt class="literal">nroff</tt> and <tt class="literal">troff</tt>honors the leading whitespace literally.</p><p>Note: the canonical reference for <tt class="literal">nroff</tt>/<tt class="literal">troff</tt> is<em class="citetitle">Bell Labs Computing Science Technical Report #54,Troff User's Manual</em>,by J.F. Ossanna and B.W. Kernighan.It is available in PostScript from<a href="http://cm.bell-labs.com/cm/cs/cstr/54.ps.gz">http://cm.bell-labs.com/cm/cs/cstr/54.ps.gz</a>.You should read it if you plan to do any serious work in<tt class="literal">nroff</tt>/<tt class="literal">troff</tt> (such as writing or modifyingmacro packages).This document explains the ideas ofdiversions,environments,fields,registers,strings,andtraps.</p><hr width="684" align="left" /><div class="navbar"><table width="684" border="0"><tr><td align="left" valign="top" width="228"><a href="ch12_03.htm"><img src="../gifs/txtpreva.gif" alt="Previous" border="0" /></a></td><td align="center" valign="top" width="228"><a href="index.htm"><img src="../gifs/txthome.gif" alt="Home" border="0" /></a></td><td align="right" valign="top" width="228"><a href="ch12_05.htm"><img src="../gifs/txtnexta.gif" alt="Next" border="0" /></a></td></tr><tr><td align="left" valign="top" width="228">12.3. Conceptual Overview</td><td align="center" valign="top" width="228"><a href="index/index.htm"><img src="../gifs/index.gif" alt="Book Index" border="0" /></a></td><td align="right" valign="top" width="228">12.5. Group Summary of Requests</td></tr></table></div><hr width="684" align="left" /><img src="../gifs/navbar.gif" usemap="#library-map" border="0" alt="Library Navigation Links" /><p><p><font size="-1"><a href="copyrght.htm">Copyright © 2003</a> O'Reilly & Associates. All rights reserved.</font></p><map name="library-map"><area shape="rect" coords="1,0,88,96" href="../index.htm"><area shape="rect" coords="90,0,165,96" href="../upt/index.htm"><area shape="rect" coords="168,1,253,107" href="../mac/index.htm"><area shape="rect" coords="255,0,335,97" href="../korn/index.htm"><area shape="rect" coords="337,0,415,109" href="../unixnut/index.htm"><area shape="rect" coords="417,0,512,122" href="../sedawk/index.htm"><area shape="rect" coords="514,0,605,105" href="../lunix/index.htm"><area shape="rect" coords="611,2,694,121" href="../vi/index.htm"></map></body></html>⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -