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Changes to manual/html_node/Fundamental-Structure.html
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From: |
Karl Berry |
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Subject: |
Changes to manual/html_node/Fundamental-Structure.html |
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Date: |
Sun, 24 May 2009 18:43:08 +0000 |
CVSROOT: /web/grep
Module name: grep
Changes by: Karl Berry <karl> 09/05/24 18:43:01
Index: manual/html_node/Fundamental-Structure.html
===================================================================
RCS file: manual/html_node/Fundamental-Structure.html
diff -N manual/html_node/Fundamental-Structure.html
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ manual/html_node/Fundamental-Structure.html 24 May 2009 18:42:58 -0000
1.1
@@ -0,0 +1,93 @@
+<html lang="en">
+<head>
+<title>Fundamental Structure - GNU Grep 2.5.4</title>
+<meta http-equiv="Content-Type" content="text/html">
+<meta name="description" content="GNU Grep 2.5.4">
+<meta name="generator" content="makeinfo 4.13">
+<link title="Top" rel="start" href="index.html#Top">
+<link rel="up" href="Regular-Expressions.html#Regular-Expressions"
title="Regular Expressions">
+<link rel="next"
href="Character-Classes-and-Bracket-Expressions.html#Character-Classes-and-Bracket-Expressions"
title="Character Classes and Bracket Expressions">
+<link href="http://www.gnu.org/software/texinfo/"; rel="generator-home"
title="Texinfo Homepage">
+<!--
+This manual is for `grep', a pattern matching engine.
+
+Copyright (C) 1999, 2000, 2001, 2002, 2005, 2008, 2009 Free
+Software Foundation, Inc.
+
+ Permission is granted to copy, distribute and/or modify this
+ document under the terms of the GNU Free Documentation License,
+ Version 1.3 or any later version published by the Free Software
+ Foundation; with no Invariant Sections, with no Front-Cover Texts,
+ and with no Back-Cover Texts. A copy of the license is included
+ in the section entitled ``GNU Free Documentation License''.
+ -->
+<meta http-equiv="Content-Style-Type" content="text/css">
+<style type="text/css"><!--
+ pre.display { font-family:inherit }
+ pre.format { font-family:inherit }
+ pre.smalldisplay { font-family:inherit; font-size:smaller }
+ pre.smallformat { font-family:inherit; font-size:smaller }
+ pre.smallexample { font-size:smaller }
+ pre.smalllisp { font-size:smaller }
+ span.sc { font-variant:small-caps }
+ span.roman { font-family:serif; font-weight:normal; }
+ span.sansserif { font-family:sans-serif; font-weight:normal; }
+--></style>
+</head>
+<body>
+<div class="node">
+<a name="Fundamental-Structure"></a>
+<p>
+Next: <a rel="next" accesskey="n"
href="Character-Classes-and-Bracket-Expressions.html#Character-Classes-and-Bracket-Expressions">Character
Classes and Bracket Expressions</a>,
+Up: <a rel="up" accesskey="u"
href="Regular-Expressions.html#Regular-Expressions">Regular Expressions</a>
+<hr>
+</div>
+
+<h3 class="section">3.1 Fundamental Structure</h3>
+
+<p>The fundamental building blocks are the regular expressions that match
+a single character.
+Most characters, including all letters and digits,
+are regular expressions that match themselves.
+Any meta-character
+with special meaning may be quoted by preceding it with a backslash.
+
+ <p>A regular expression may be followed by one of several
+repetition operators:
+
+ <dl>
+<dt>‘<samp><span class="samp">.</span></samp>’<dd><a
name="index-g_t_002e-179"></a><a name="index-dot-180"></a><a
name="index-period-181"></a>The period ‘<samp><span
class="samp">.</span></samp>’ matches any single character.
+
+ <br><dt>‘<samp><span class="samp">?</span></samp>’<dd><a
name="index-g_t_003f-182"></a><a name="index-question-mark-183"></a><a
name="index-match-expression-at-most-once-184"></a>The preceding item is
optional and will be matched at most once.
+
+ <br><dt>‘<samp><span class="samp">*</span></samp>’<dd><a
name="index-g_t_002a-185"></a><a name="index-asterisk-186"></a><a
name="index-match-expression-zero-or-more-times-187"></a>The preceding item
will be matched zero or more times.
+
+ <br><dt>‘<samp><span class="samp">+</span></samp>’<dd><a
name="index-g_t_002b-188"></a><a name="index-plus-sign-189"></a><a
name="index-match-expression-one-or-more-times-190"></a>The preceding item will
be matched one or more times.
+
+ <br><dt>‘<samp><span class="samp">{</span><var>n</var><span
class="samp">}</span></samp>’<dd><a
name="index-g_t_0040_007b_0040var_007bn_007d_0040_007d-191"></a><a
name="index-braces_002c-one-argument-192"></a><a
name="index-match-expression-_0040var_007bn_007d-times-193"></a>The preceding
item is matched exactly <var>n</var> times.
+
+ <br><dt>‘<samp><span class="samp">{</span><var>n</var><span
class="samp">,}</span></samp>’<dd><a
name="index-g_t_0040_007b_0040var_007bn_007d_002c_0040_007d-194"></a><a
name="index-braces_002c-second-argument-omitted-195"></a><a
name="index-match-expression-_0040var_007bn_007d-or-more-times-196"></a>The
preceding item is matched <var>n</var> or more times.
+
+ <br><dt>‘<samp><span class="samp">{,</span><var>m</var><span
class="samp">}</span></samp>’<dd><a
name="index-g_t_0040_007b_002c_0040var_007bm_007d_0040_007d-197"></a><a
name="index-braces_002c-first-argument-omitted-198"></a><a
name="index-match-expression-at-most-_0040var_007bm_007d-times-199"></a>The
preceding item is matched at most <var>m</var> times.
+
+ <br><dt>‘<samp><span class="samp">{</span><var>n</var><span
class="samp">,</span><var>m</var><span
class="samp">}</span></samp>’<dd><a
name="index-g_t_0040_007b_0040var_007bn_007d_002c_0040var_007bm_007d_0040_007d-200"></a><a
name="index-braces_002c-two-arguments-201"></a><a
name="index-match-expression-from-_0040var_007bn_007d-to-_0040var_007bm_007d-times-202"></a>The
preceding item is matched at least <var>n</var> times, but not more than
+<var>m</var> times.
+
+ </dl>
+
+ <p>Two regular expressions may be concatenated;
+the resulting regular expression
+matches any string formed by concatenating two substrings
+that respectively match the concatenated expressions.
+
+ <p>Two regular expressions may be joined by the infix operator
‘<samp><span class="samp">|</span></samp>’;
+the resulting regular expression
+matches any string matching either alternalte expression.
+
+ <p>Repetition takes precedence over concatenation,
+which in turn takes precedence over alternation.
+A whole expression may be enclosed in parentheses
+to override these precedence rules and form a subexpression.
+
+ </body></html>
+
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