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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><meta name="generator" content="HTML Tidy, see www.w3.org"><meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"><link type="text/css" rel="stylesheet" href="style.css"><!-- Generated by The Open Group's rhtm tool v1.2.1 --><!-- Copyright (c) 2001-2003 The Open Group, All Rights Reserved --><title>File Format Notation</title></head><body bgcolor="white"><basefont size="3"> <!--header start--><center><font size="2">The Open Group Base Specifications Issue 6<br>IEEE Std 1003.1, 2003 Edition<br>Copyright © 2001-2003 The IEEE and The Open Group, All Rights reserved.</font></center><!--header end--><hr size="2" noshade><h2><a name="tag_05"></a>File Format Notation</h2><p>The STDIN, STDOUT, STDERR, INPUT FILES, and OUTPUT FILES sections of the utility descriptions use a syntax to describe the dataorganization within the files, when that organization is not otherwise obvious. The syntax is similar to that used by the SystemInterfaces volume of IEEE Std 1003.1-2001 <a href="../functions/printf.html"><i>printf</i>()</a> function, as describedin this chapter. When used in STDIN or INPUT FILES sections of the utility descriptions, this syntax describes the format thatcould have been used to write the text to be read, not a format that could be used by the System Interfaces volume ofIEEE Std 1003.1-2001 <a href="../functions/scanf.html"><i>scanf</i>()</a> function to read the input file.</p><p>The description of an individual record is as follows:</p><blockquote><pre><tt>"<</tt><i>format</i><tt>>",</tt> <b>[</b><tt><</tt><i>arg1</i><tt>>, <</tt><i>arg2</i><tt>>,..., <</tt><i>argn</i><tt>></tt><b>]</b></pre></blockquote><p>The <i>format</i> is a character string that contains three types of objects defined below:</p><ol><li><p><i>Characters</i> that are not "escape sequences" or "conversion specifications", as described below, shall be copied to theoutput.</p></li><li><p><i>Escape Sequences</i> represent non-graphic characters.</p></li><li><p><i>Conversion Specifications</i> specify the output format of each argument; see below.</p></li></ol><p>The following characters have the following special meaning in the format string:</p><dl compact><dt><tt>''</tt></dt><dd>(An empty character position.) Represents one or more <blank>s.</dd><dt><tt><img src="../images/delta.gif" border="0"></tt></dt><dd>Represents exactly one <space>.</dd></dl><p><a href="#tagtcjh_2">Escape Sequences and Associated Actions</a> lists escape sequences and associated actions on displaydevices capable of the action.<br></p><center><b><a name="tagtcjh_2"></a> Table: Escape Sequences and Associated Actions</b></center><center><table border="1" cellpadding="3" align="center"><tr valign="top"><th align="center"><p class="tent"><b>Escape</b></p></th><th align="center"><p class="tent"><b>Represents</b></p></th><th align="center"><p class="tent"><b> </b></p></th></tr><tr valign="top"><th align="center"><p class="tent"><b>Sequence</b></p></th><th align="center"><p class="tent"><b>Character</b></p></th><th align="center"><p class="tent"><b>Terminal Action</b></p></th></tr><tr valign="top"><td align="center"><p class="tent"><tt>'\\'</tt> </p></td><td align="left"><p class="tent">backslash</p></td><td align="left"><p class="tent">Print the character <tt>'\'</tt> .</p></td></tr><tr valign="top"><td align="center"><p class="tent"><tt>'\a'</tt> </p></td><td align="left"><p class="tent">alert</p></td><td align="left"><p class="tent">Attempt to alert the user through audible or visible notification.</p></td></tr><tr valign="top"><td align="center"><p class="tent"><tt>'\b'</tt> </p></td><td align="left"><p class="tent">backspace</p></td><td align="left"><p class="tent">Move the printing position to one column before the current position, unless the current position is the start of aline.</p></td></tr><tr valign="top"><td align="center"><p class="tent"><tt>'\f'</tt> </p></td><td align="left"><p class="tent">form-feed</p></td><td align="left"><p class="tent">Move the printing position to the initial printing position of the next logical page.</p></td></tr><tr valign="top"><td align="center"><p class="tent"><tt>'\n'</tt> </p></td><td align="left"><p class="tent">newline</p></td><td align="left"><p class="tent">Move the printing position to the start of the next line.</p></td></tr><tr valign="top"><td align="center"><p class="tent"><tt>'\r'</tt> </p></td><td align="left"><p class="tent">carriage-return</p></td><td align="left"><p class="tent">Move the printing position to the start of the current line.</p></td></tr><tr valign="top"><td align="center"><p class="tent"><tt>'\t'</tt> </p></td><td align="left"><p class="tent">tab</p></td><td align="left"><p class="tent">Move the printing position to the next tab position on the current line. If there are no more tab positionsremaining on the line, the behavior is undefined.</p></td></tr><tr valign="top"><td align="center"><p class="tent"><tt>'\v'</tt> </p></td><td align="left"><p class="tent">vertical-tab</p>⌨️ 快捷键说明
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