1 76193d7c 2003-09-30 devnull .TH REGEXP9 7
  2 76193d7c 2003-09-30 devnull .de EX
  3 76193d7c 2003-09-30 devnull .nf
  4 76193d7c 2003-09-30 devnull .ft B
  5 76193d7c 2003-09-30 devnull ..
  6 76193d7c 2003-09-30 devnull .de EE
  7 76193d7c 2003-09-30 devnull .fi
  8 76193d7c 2003-09-30 devnull .ft R
  9 76193d7c 2003-09-30 devnull ..
 10 76193d7c 2003-09-30 devnull .de LR
 11 76193d7c 2003-09-30 devnull .if t .BR \\$1 \\$2
 12 76193d7c 2003-09-30 devnull .if n .RB ` \\$1 '\\$2
 13 76193d7c 2003-09-30 devnull ..
 14 76193d7c 2003-09-30 devnull .de L
 15 76193d7c 2003-09-30 devnull .nh
 16 76193d7c 2003-09-30 devnull .if t .B \\$1
 17 76193d7c 2003-09-30 devnull .if n .RB ` \\$1 '
 18 76193d7c 2003-09-30 devnull ..
 19 76193d7c 2003-09-30 devnull .SH NAME
 20 76193d7c 2003-09-30 devnull regexp9 \- Plan 9 regular expression notation
 21 76193d7c 2003-09-30 devnull .SH DESCRIPTION
 22 76193d7c 2003-09-30 devnull This manual page describes the regular expression
 23 76193d7c 2003-09-30 devnull syntax used by the Plan 9 regular expression library
 24 76193d7c 2003-09-30 devnull .IR regexp9 (3).
 25 76193d7c 2003-09-30 devnull It is the form used by
 26 76193d7c 2003-09-30 devnull .IR egrep (1)
 27 76193d7c 2003-09-30 devnull before
 28 76193d7c 2003-09-30 devnull .I egrep
 29 76193d7c 2003-09-30 devnull got complicated.
 30 76193d7c 2003-09-30 devnull .PP
 31 76193d7c 2003-09-30 devnull A 
 32 76193d7c 2003-09-30 devnull .I "regular expression"
 33 76193d7c 2003-09-30 devnull specifies
 34 76193d7c 2003-09-30 devnull a set of strings of characters.
 35 76193d7c 2003-09-30 devnull A member of this set of strings is said to be
 36 76193d7c 2003-09-30 devnull .I matched
 37 76193d7c 2003-09-30 devnull by the regular expression.  In many applications
 38 76193d7c 2003-09-30 devnull a delimiter character, commonly
 39 76193d7c 2003-09-30 devnull .LR / ,
 40 76193d7c 2003-09-30 devnull bounds a regular expression.
 41 76193d7c 2003-09-30 devnull In the following specification for regular expressions
 42 76193d7c 2003-09-30 devnull the word `character' means any character (rune) but newline.
 43 76193d7c 2003-09-30 devnull .PP
 44 76193d7c 2003-09-30 devnull The syntax for a regular expression
 45 76193d7c 2003-09-30 devnull .B e0
 46 76193d7c 2003-09-30 devnull is
 47 76193d7c 2003-09-30 devnull .IP
 48 76193d7c 2003-09-30 devnull .EX
 49 76193d7c 2003-09-30 devnull e3:  literal | charclass | '.' | '^' | '$' | '(' e0 ')'
 50 76193d7c 2003-09-30 devnull 
 51 76193d7c 2003-09-30 devnull e2:  e3
 52 76193d7c 2003-09-30 devnull   |  e2 REP
 53 76193d7c 2003-09-30 devnull 
 54 76193d7c 2003-09-30 devnull REP: '*' | '+' | '?'
 55 76193d7c 2003-09-30 devnull 
 56 76193d7c 2003-09-30 devnull e1:  e2
 57 76193d7c 2003-09-30 devnull   |  e1 e2
 58 76193d7c 2003-09-30 devnull 
 59 76193d7c 2003-09-30 devnull e0:  e1
 60 76193d7c 2003-09-30 devnull   |  e0 '|' e1
 61 76193d7c 2003-09-30 devnull .EE
 62 76193d7c 2003-09-30 devnull .PP
 63 76193d7c 2003-09-30 devnull A
 64 76193d7c 2003-09-30 devnull .B literal
 65 76193d7c 2003-09-30 devnull is any non-metacharacter, or a metacharacter
 66 76193d7c 2003-09-30 devnull (one of
 67 76193d7c 2003-09-30 devnull .BR .*+?[]()|\e^$ ),
 68 76193d7c 2003-09-30 devnull or the delimiter
 69 76193d7c 2003-09-30 devnull preceded by 
 70 76193d7c 2003-09-30 devnull .LR \e .
 71 76193d7c 2003-09-30 devnull .PP
 72 76193d7c 2003-09-30 devnull A
 73 76193d7c 2003-09-30 devnull .B charclass
 74 76193d7c 2003-09-30 devnull is a nonempty string
 75 76193d7c 2003-09-30 devnull .I s
 76 76193d7c 2003-09-30 devnull bracketed
 77 76193d7c 2003-09-30 devnull .BI [ \|s\| ]
 78 76193d7c 2003-09-30 devnull (or
 79 76193d7c 2003-09-30 devnull .BI [^ s\| ]\fR);
 80 76193d7c 2003-09-30 devnull it matches any character in (or not in)
 81 76193d7c 2003-09-30 devnull .IR s .
 82 76193d7c 2003-09-30 devnull A negated character class never
 83 76193d7c 2003-09-30 devnull matches newline.
 84 76193d7c 2003-09-30 devnull A substring 
 85 76193d7c 2003-09-30 devnull .IB a - b\f1,
 86 76193d7c 2003-09-30 devnull with
 87 76193d7c 2003-09-30 devnull .I a
 88 76193d7c 2003-09-30 devnull and
 89 76193d7c 2003-09-30 devnull .I b
 90 76193d7c 2003-09-30 devnull in ascending
 91 76193d7c 2003-09-30 devnull order, stands for the inclusive
 92 76193d7c 2003-09-30 devnull range of
 93 76193d7c 2003-09-30 devnull characters between
 94 76193d7c 2003-09-30 devnull .I a
 95 76193d7c 2003-09-30 devnull and
 96 76193d7c 2003-09-30 devnull .IR b .
 97 76193d7c 2003-09-30 devnull In 
 98 76193d7c 2003-09-30 devnull .IR s ,
 99 76193d7c 2003-09-30 devnull the metacharacters
100 76193d7c 2003-09-30 devnull .LR - ,
101 76193d7c 2003-09-30 devnull .LR ] ,
102 76193d7c 2003-09-30 devnull an initial
103 76193d7c 2003-09-30 devnull .LR ^ ,
104 76193d7c 2003-09-30 devnull and the regular expression delimiter
105 76193d7c 2003-09-30 devnull must be preceded by a
106 76193d7c 2003-09-30 devnull .LR \e ;
107 76193d7c 2003-09-30 devnull other metacharacters 
108 76193d7c 2003-09-30 devnull have no special meaning and
109 76193d7c 2003-09-30 devnull may appear unescaped.
110 76193d7c 2003-09-30 devnull .PP
111 76193d7c 2003-09-30 devnull A 
112 76193d7c 2003-09-30 devnull .L .
113 76193d7c 2003-09-30 devnull matches any character.
114 76193d7c 2003-09-30 devnull .PP
115 76193d7c 2003-09-30 devnull A
116 76193d7c 2003-09-30 devnull .L ^
117 76193d7c 2003-09-30 devnull matches the beginning of a line;
118 76193d7c 2003-09-30 devnull .L $
119 76193d7c 2003-09-30 devnull matches the end of the line.
120 76193d7c 2003-09-30 devnull .PP
121 76193d7c 2003-09-30 devnull The 
122 76193d7c 2003-09-30 devnull .B REP
123 76193d7c 2003-09-30 devnull operators match zero or more
124 76193d7c 2003-09-30 devnull .RB ( * ),
125 76193d7c 2003-09-30 devnull one or more
126 76193d7c 2003-09-30 devnull .RB ( + ),
127 76193d7c 2003-09-30 devnull zero or one
128 76193d7c 2003-09-30 devnull .RB ( ? ),
129 76193d7c 2003-09-30 devnull instances respectively of the preceding regular expression 
130 76193d7c 2003-09-30 devnull .BR e2 .
131 76193d7c 2003-09-30 devnull .PP
132 76193d7c 2003-09-30 devnull A concatenated regular expression,
133 76193d7c 2003-09-30 devnull .BR "e1\|e2" ,
134 76193d7c 2003-09-30 devnull matches a match to 
135 76193d7c 2003-09-30 devnull .B e1
136 76193d7c 2003-09-30 devnull followed by a match to
137 76193d7c 2003-09-30 devnull .BR e2 .
138 76193d7c 2003-09-30 devnull .PP
139 76193d7c 2003-09-30 devnull An alternative regular expression,
140 76193d7c 2003-09-30 devnull .BR "e0\||\|e1" ,
141 76193d7c 2003-09-30 devnull matches either a match to
142 76193d7c 2003-09-30 devnull .B e0
143 76193d7c 2003-09-30 devnull or a match to
144 76193d7c 2003-09-30 devnull .BR e1 .
145 76193d7c 2003-09-30 devnull .PP
146 76193d7c 2003-09-30 devnull A match to any part of a regular expression
147 76193d7c 2003-09-30 devnull extends as far as possible without preventing
148 76193d7c 2003-09-30 devnull a match to the remainder of the regular expression.
149 76193d7c 2003-09-30 devnull .SH "SEE ALSO"
150 76193d7c 2003-09-30 devnull .IR regexp9 (3)