1 cfa37a7b 2004-04-10 devnull .TH REGEXP9 7
  2 cfa37a7b 2004-04-10 devnull .de EX
  3 cfa37a7b 2004-04-10 devnull .nf
  4 cfa37a7b 2004-04-10 devnull .ft B
  5 cfa37a7b 2004-04-10 devnull ..
  6 cfa37a7b 2004-04-10 devnull .de EE
  7 cfa37a7b 2004-04-10 devnull .fi
  8 cfa37a7b 2004-04-10 devnull .ft R
  9 cfa37a7b 2004-04-10 devnull ..
 10 cfa37a7b 2004-04-10 devnull .de LR
 11 cfa37a7b 2004-04-10 devnull .if t .BR \\$1 \\$2
 12 cfa37a7b 2004-04-10 devnull .if n .RB ` \\$1 '\\$2
 13 cfa37a7b 2004-04-10 devnull ..
 14 cfa37a7b 2004-04-10 devnull .de L
 15 cfa37a7b 2004-04-10 devnull .nh
 16 cfa37a7b 2004-04-10 devnull .if t .B \\$1
 17 cfa37a7b 2004-04-10 devnull .if n .RB ` \\$1 '
 18 cfa37a7b 2004-04-10 devnull ..
 19 cfa37a7b 2004-04-10 devnull .SH NAME
 20 cfa37a7b 2004-04-10 devnull regexp9 \- Plan 9 regular expression notation
 21 cfa37a7b 2004-04-10 devnull .SH DESCRIPTION
 22 cfa37a7b 2004-04-10 devnull This manual page describes the regular expression
 23 cfa37a7b 2004-04-10 devnull syntax used by the Plan 9 regular expression library
 24 cfa37a7b 2004-04-10 devnull .IR regexp9 (3).
 25 cfa37a7b 2004-04-10 devnull It is the form used by
 26 cfa37a7b 2004-04-10 devnull .IR egrep (1)
 27 cfa37a7b 2004-04-10 devnull before
 28 cfa37a7b 2004-04-10 devnull .I egrep
 29 cfa37a7b 2004-04-10 devnull got complicated.
 30 cfa37a7b 2004-04-10 devnull .PP
 31 cfa37a7b 2004-04-10 devnull A 
 32 cfa37a7b 2004-04-10 devnull .I "regular expression"
 33 cfa37a7b 2004-04-10 devnull specifies
 34 cfa37a7b 2004-04-10 devnull a set of strings of characters.
 35 cfa37a7b 2004-04-10 devnull A member of this set of strings is said to be
 36 cfa37a7b 2004-04-10 devnull .I matched
 37 cfa37a7b 2004-04-10 devnull by the regular expression.  In many applications
 38 cfa37a7b 2004-04-10 devnull a delimiter character, commonly
 39 cfa37a7b 2004-04-10 devnull .LR / ,
 40 cfa37a7b 2004-04-10 devnull bounds a regular expression.
 41 cfa37a7b 2004-04-10 devnull In the following specification for regular expressions
 42 cfa37a7b 2004-04-10 devnull the word `character' means any character (rune) but newline.
 43 cfa37a7b 2004-04-10 devnull .PP
 44 cfa37a7b 2004-04-10 devnull The syntax for a regular expression
 45 cfa37a7b 2004-04-10 devnull .B e0
 46 cfa37a7b 2004-04-10 devnull is
 47 cfa37a7b 2004-04-10 devnull .IP
 48 cfa37a7b 2004-04-10 devnull .EX
 49 cfa37a7b 2004-04-10 devnull e3:  literal | charclass | '.' | '^' | '$' | '(' e0 ')'
 50 cfa37a7b 2004-04-10 devnull 
 51 cfa37a7b 2004-04-10 devnull e2:  e3
 52 cfa37a7b 2004-04-10 devnull   |  e2 REP
 53 cfa37a7b 2004-04-10 devnull 
 54 cfa37a7b 2004-04-10 devnull REP: '*' | '+' | '?'
 55 cfa37a7b 2004-04-10 devnull 
 56 cfa37a7b 2004-04-10 devnull e1:  e2
 57 cfa37a7b 2004-04-10 devnull   |  e1 e2
 58 cfa37a7b 2004-04-10 devnull 
 59 cfa37a7b 2004-04-10 devnull e0:  e1
 60 cfa37a7b 2004-04-10 devnull   |  e0 '|' e1
 61 cfa37a7b 2004-04-10 devnull .EE
 62 cfa37a7b 2004-04-10 devnull .PP
 63 cfa37a7b 2004-04-10 devnull A
 64 cfa37a7b 2004-04-10 devnull .B literal
 65 cfa37a7b 2004-04-10 devnull is any non-metacharacter, or a metacharacter
 66 cfa37a7b 2004-04-10 devnull (one of
 67 cfa37a7b 2004-04-10 devnull .BR .*+?[]()|\e^$ ),
 68 cfa37a7b 2004-04-10 devnull or the delimiter
 69 cfa37a7b 2004-04-10 devnull preceded by 
 70 cfa37a7b 2004-04-10 devnull .LR \e .
 71 cfa37a7b 2004-04-10 devnull .PP
 72 cfa37a7b 2004-04-10 devnull A
 73 cfa37a7b 2004-04-10 devnull .B charclass
 74 cfa37a7b 2004-04-10 devnull is a nonempty string
 75 cfa37a7b 2004-04-10 devnull .I s
 76 cfa37a7b 2004-04-10 devnull bracketed
 77 cfa37a7b 2004-04-10 devnull .BI [ \|s\| ]
 78 cfa37a7b 2004-04-10 devnull (or
 79 cfa37a7b 2004-04-10 devnull .BI [^ s\| ]\fR);
 80 cfa37a7b 2004-04-10 devnull it matches any character in (or not in)
 81 cfa37a7b 2004-04-10 devnull .IR s .
 82 cfa37a7b 2004-04-10 devnull A negated character class never
 83 cfa37a7b 2004-04-10 devnull matches newline.
 84 cfa37a7b 2004-04-10 devnull A substring 
 85 cfa37a7b 2004-04-10 devnull .IB a - b\f1,
 86 cfa37a7b 2004-04-10 devnull with
 87 cfa37a7b 2004-04-10 devnull .I a
 88 cfa37a7b 2004-04-10 devnull and
 89 cfa37a7b 2004-04-10 devnull .I b
 90 cfa37a7b 2004-04-10 devnull in ascending
 91 cfa37a7b 2004-04-10 devnull order, stands for the inclusive
 92 cfa37a7b 2004-04-10 devnull range of
 93 cfa37a7b 2004-04-10 devnull characters between
 94 cfa37a7b 2004-04-10 devnull .I a
 95 cfa37a7b 2004-04-10 devnull and
 96 cfa37a7b 2004-04-10 devnull .IR b .
 97 cfa37a7b 2004-04-10 devnull In 
 98 cfa37a7b 2004-04-10 devnull .IR s ,
 99 cfa37a7b 2004-04-10 devnull the metacharacters
100 cfa37a7b 2004-04-10 devnull .LR - ,
101 cfa37a7b 2004-04-10 devnull .LR ] ,
102 cfa37a7b 2004-04-10 devnull an initial
103 cfa37a7b 2004-04-10 devnull .LR ^ ,
104 cfa37a7b 2004-04-10 devnull and the regular expression delimiter
105 cfa37a7b 2004-04-10 devnull must be preceded by a
106 cfa37a7b 2004-04-10 devnull .LR \e ;
107 cfa37a7b 2004-04-10 devnull other metacharacters 
108 cfa37a7b 2004-04-10 devnull have no special meaning and
109 cfa37a7b 2004-04-10 devnull may appear unescaped.
110 cfa37a7b 2004-04-10 devnull .PP
111 cfa37a7b 2004-04-10 devnull A 
112 cfa37a7b 2004-04-10 devnull .L .
113 cfa37a7b 2004-04-10 devnull matches any character.
114 cfa37a7b 2004-04-10 devnull .PP
115 cfa37a7b 2004-04-10 devnull A
116 cfa37a7b 2004-04-10 devnull .L ^
117 cfa37a7b 2004-04-10 devnull matches the beginning of a line;
118 cfa37a7b 2004-04-10 devnull .L $
119 cfa37a7b 2004-04-10 devnull matches the end of the line.
120 cfa37a7b 2004-04-10 devnull .PP
121 cfa37a7b 2004-04-10 devnull The 
122 cfa37a7b 2004-04-10 devnull .B REP
123 cfa37a7b 2004-04-10 devnull operators match zero or more
124 cfa37a7b 2004-04-10 devnull .RB ( * ),
125 cfa37a7b 2004-04-10 devnull one or more
126 cfa37a7b 2004-04-10 devnull .RB ( + ),
127 cfa37a7b 2004-04-10 devnull zero or one
128 cfa37a7b 2004-04-10 devnull .RB ( ? ),
129 cfa37a7b 2004-04-10 devnull instances respectively of the preceding regular expression 
130 cfa37a7b 2004-04-10 devnull .BR e2 .
131 cfa37a7b 2004-04-10 devnull .PP
132 cfa37a7b 2004-04-10 devnull A concatenated regular expression,
133 cfa37a7b 2004-04-10 devnull .BR "e1\|e2" ,
134 cfa37a7b 2004-04-10 devnull matches a match to 
135 cfa37a7b 2004-04-10 devnull .B e1
136 cfa37a7b 2004-04-10 devnull followed by a match to
137 cfa37a7b 2004-04-10 devnull .BR e2 .
138 cfa37a7b 2004-04-10 devnull .PP
139 cfa37a7b 2004-04-10 devnull An alternative regular expression,
140 cfa37a7b 2004-04-10 devnull .BR "e0\||\|e1" ,
141 cfa37a7b 2004-04-10 devnull matches either a match to
142 cfa37a7b 2004-04-10 devnull .B e0
143 cfa37a7b 2004-04-10 devnull or a match to
144 cfa37a7b 2004-04-10 devnull .BR e1 .
145 cfa37a7b 2004-04-10 devnull .PP
146 cfa37a7b 2004-04-10 devnull A match to any part of a regular expression
147 cfa37a7b 2004-04-10 devnull extends as far as possible without preventing
148 cfa37a7b 2004-04-10 devnull a match to the remainder of the regular expression.
149 cfa37a7b 2004-04-10 devnull .SH "SEE ALSO"
150 cfa37a7b 2004-04-10 devnull .IR regexp9 (3)