CVSROOT: /sources/m4
Module name: m4
Changes by: Gary V. Vaughan <gary> 06/07/13 23:35:16
Index: doc/regexprops-generic.texi
===================================================================
RCS file: doc/regexprops-generic.texi
diff -N doc/regexprops-generic.texi
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ doc/regexprops-generic.texi 13 Jul 2006 23:35:16 -0000 1.1
@@ -0,0 +1,703 @@
[EMAIL PROTECTED]
+* awk regular expression syntax::
+* egrep regular expression syntax::
+* ed regular expression syntax::
+* emacs regular expression syntax::
+* gnu-awk regular expression syntax::
+* grep regular expression syntax::
+* posix-awk regular expression syntax::
+* posix-basic regular expression syntax::
+* posix-egrep regular expression syntax::
+* posix-extended regular expression syntax::
+* posix-minimal-basic regular expression syntax::
+* sed regular expression syntax::
[EMAIL PROTECTED] menu
+
[EMAIL PROTECTED] awk regular expression syntax
[EMAIL PROTECTED] @samp{awk} regular expression syntax
+
+
+The character @samp{.} matches any single character except the null character.
+
+
[EMAIL PROTECTED] @samp
+
[EMAIL PROTECTED] +
+indicates that the regular expression should match one or more occurrences of
the previous atom or regexp.
[EMAIL PROTECTED] ?
+indicates that the regular expression should match zero or one occurrence of
the previous atom or regexp.
[EMAIL PROTECTED] \+
+matches a @samp{+}
[EMAIL PROTECTED] \?
+matches a @samp{?}.
[EMAIL PROTECTED] table
+
+
+Bracket expressions are used to match ranges of characters. Bracket
expressions where the range is backward, for example @samp{[z-a]}, are invalid.
Within square brackets, @samp{\} can be used to quote the following character.
Character classes are not supported, so for example you would need to use
@samp{[0-9]} instead of @samp{[[:digit:]]}.
+
+GNU extensions are not supported and so @samp{\w}, @samp{\W}, @samp{\<},
@samp{\>}, @samp{\b}, @samp{\B}, @samp{\`}, and @samp{\'} match @samp{w},
@samp{W}, @samp{<}, @samp{>}, @samp{b}, @samp{B}, @samp{`}, and @samp{'}
respectively.
+
+Grouping is performed with parentheses @samp{()}. An unmatched @samp{)}
matches just itself. A backslash followed by a digit matches that digit.
+
+The alternation operator is @samp{|}.
+
+The characters @samp{^} and @samp{$} always represent the beginning and end of
a string respectively, except within square brackets. Within brackets,
@samp{^} can be used to invert the membership of the character class being
specified.
+
[EMAIL PROTECTED], @samp{+} and @samp{?} are special at any point in a regular
expression except:
[EMAIL PROTECTED]
+
[EMAIL PROTECTED] At the beginning of a regular expression
+
[EMAIL PROTECTED] After an open-group, signified by
[EMAIL PROTECTED](}
[EMAIL PROTECTED] After the alternation operator @samp{|}
+
[EMAIL PROTECTED] enumerate
+
+
+
+
+The longest possible match is returned; this applies to the regular expression
as a whole and (subject to this constraint) to subexpressions within groups.
+
+
[EMAIL PROTECTED] egrep regular expression syntax
[EMAIL PROTECTED] @samp{egrep} regular expression syntax
+
+
+The character @samp{.} matches any single character except newline.
+
+
[EMAIL PROTECTED] @samp
+
[EMAIL PROTECTED] +
+indicates that the regular expression should match one or more occurrences of
the previous atom or regexp.
[EMAIL PROTECTED] ?
+indicates that the regular expression should match zero or one occurrence of
the previous atom or regexp.
[EMAIL PROTECTED] \+
+matches a @samp{+}
[EMAIL PROTECTED] \?
+matches a @samp{?}.
[EMAIL PROTECTED] table
+
+
+Bracket expressions are used to match ranges of characters. Bracket
expressions where the range is backward, for example @samp{[z-a]}, are ignored.
Within square brackets, @samp{\} is taken literally. Character classes are
supported; for example @samp{[[:digit:]]} will match a single decimal digit.
Non-matching lists @[EMAIL PROTECTED] do not ever match newline.
+
+GNU extensions are supported:
[EMAIL PROTECTED]
+
[EMAIL PROTECTED] @samp{\w} matches a character within a word
+
[EMAIL PROTECTED] @samp{\W} matches a character which is not within a word
+
[EMAIL PROTECTED] @samp{\<} matches the beginning of a word
+
[EMAIL PROTECTED] @samp{\>} matches the end of a word
+
[EMAIL PROTECTED] @samp{\b} matches a word boundary
+
[EMAIL PROTECTED] @samp{\B} matches characters which are not a word boundary
+
[EMAIL PROTECTED] @samp{\`} matches the beginning of the whole input
+
[EMAIL PROTECTED] @samp{\'} matches the end of the whole input
+
[EMAIL PROTECTED] enumerate
+
+
+Grouping is performed with parentheses @samp{()}. A backslash followed by a
digit acts as a back-reference and matches the same thing as the previous
grouped expression indicated by that number. For example @samp{\2} matches the
second group expression. The order of group expressions is determined by the
position of their opening parenthesis @samp{(}.
+
+The alternation operator is @samp{|}.
+
+The characters @samp{^} and @samp{$} always represent the beginning and end of
a string respectively, except within square brackets. Within brackets,
@samp{^} can be used to invert the membership of the character class being
specified.
+
+The characters @samp{*}, @samp{+} and @samp{?} are special anywhere in a
regular expression.
+
+
+
+The longest possible match is returned; this applies to the regular expression
as a whole and (subject to this constraint) to subexpressions within groups.
+
+
[EMAIL PROTECTED] ed regular expression syntax
[EMAIL PROTECTED] @samp{ed} regular expression syntax
+
+
+The character @samp{.} matches any single character except the null character.
+
+
[EMAIL PROTECTED] @samp
+
[EMAIL PROTECTED] \+
+indicates that the regular expression should match one or more occurrences of
the previous atom or regexp.
[EMAIL PROTECTED] \?
+indicates that the regular expression should match zero or one occurrence of
the previous atom or regexp.
[EMAIL PROTECTED] + and ?
+match themselves.
[EMAIL PROTECTED] table
+
+
+Bracket expressions are used to match ranges of characters. Bracket
expressions where the range is backward, for example @samp{[z-a]}, are invalid.
Within square brackets, @samp{\} is taken literally. Character classes are
supported; for example @samp{[[:digit:]]} will match a single decimal digit.
+
+GNU extensions are supported:
[EMAIL PROTECTED]
+
[EMAIL PROTECTED] @samp{\w} matches a character within a word
+
[EMAIL PROTECTED] @samp{\W} matches a character which is not within a word
+
[EMAIL PROTECTED] @samp{\<} matches the beginning of a word
+
[EMAIL PROTECTED] @samp{\>} matches the end of a word
+
[EMAIL PROTECTED] @samp{\b} matches a word boundary
+
[EMAIL PROTECTED] @samp{\B} matches characters which are not a word boundary
+
[EMAIL PROTECTED] @samp{\`} matches the beginning of the whole input
+
[EMAIL PROTECTED] @samp{\'} matches the end of the whole input
+
[EMAIL PROTECTED] enumerate
+
+
+Grouping is performed with backslashes followed by parentheses @samp{\(},
@samp{\)}. A backslash followed by a digit acts as a back-reference and
matches the same thing as the previous grouped expression indicated by that
number. For example @samp{\2} matches the second group expression. The order
of group expressions is determined by the position of their opening parenthesis
@samp{\(}.
+
+The alternation operator is @samp{\|}.
+
+The character @samp{^} only represents the beginning of a string when it
appears:
[EMAIL PROTECTED]
+
[EMAIL PROTECTED]
+At the beginning of a regular expression
+
[EMAIL PROTECTED] After an open-group, signified by
[EMAIL PROTECTED](}
+
[EMAIL PROTECTED] After the alternation operator @samp{\|}
+
[EMAIL PROTECTED] enumerate
+
+
+The character @samp{$} only represents the end of a string when it appears:
[EMAIL PROTECTED]
+
[EMAIL PROTECTED] At the end of a regular expression
+
[EMAIL PROTECTED] Before an close-group, signified by
[EMAIL PROTECTED])}
[EMAIL PROTECTED] Before the alternation operator @samp{\|}
+
[EMAIL PROTECTED] enumerate
+
+
[EMAIL PROTECTED], @samp{\+} and @samp{\?} are special at any point in a
regular expression except:
[EMAIL PROTECTED]
+
[EMAIL PROTECTED] At the beginning of a regular expression
+
[EMAIL PROTECTED] After an open-group, signified by
[EMAIL PROTECTED](}
[EMAIL PROTECTED] After the alternation operator @samp{\|}
+
[EMAIL PROTECTED] enumerate
+
+
+Intervals are specified by @[EMAIL PROTECTED] and @[EMAIL PROTECTED] Invalid
intervals such as @[EMAIL PROTECTED] are not accepted.
+
+The longest possible match is returned; this applies to the regular expression
as a whole and (subject to this constraint) to subexpressions within groups.
+
+
[EMAIL PROTECTED] emacs regular expression syntax
[EMAIL PROTECTED] @samp{emacs} regular expression syntax
+
+
+The character @samp{.} matches any single character except newline.
+
+
[EMAIL PROTECTED] @samp
+
[EMAIL PROTECTED] +
+indicates that the regular expression should match one or more occurrences of
the previous atom or regexp.
[EMAIL PROTECTED] ?
+indicates that the regular expression should match zero or one occurrence of
the previous atom or regexp.
[EMAIL PROTECTED] \+
+matches a @samp{+}
[EMAIL PROTECTED] \?
+matches a @samp{?}.
[EMAIL PROTECTED] table
+
+
+Bracket expressions are used to match ranges of characters. Bracket
expressions where the range is backward, for example @samp{[z-a]}, are ignored.
Within square brackets, @samp{\} is taken literally. Character classes are
not supported, so for example you would need to use @samp{[0-9]} instead of
@samp{[[:digit:]]}.
+
+GNU extensions are supported:
[EMAIL PROTECTED]
+
[EMAIL PROTECTED] @samp{\w} matches a character within a word
+
[EMAIL PROTECTED] @samp{\W} matches a character which is not within a word
+
[EMAIL PROTECTED] @samp{\<} matches the beginning of a word
+
[EMAIL PROTECTED] @samp{\>} matches the end of a word
+
[EMAIL PROTECTED] @samp{\b} matches a word boundary
+
[EMAIL PROTECTED] @samp{\B} matches characters which are not a word boundary
+
[EMAIL PROTECTED] @samp{\`} matches the beginning of the whole input
+
[EMAIL PROTECTED] @samp{\'} matches the end of the whole input
+
[EMAIL PROTECTED] enumerate
+
+
+Grouping is performed with backslashes followed by parentheses @samp{\(},
@samp{\)}. A backslash followed by a digit acts as a back-reference and
matches the same thing as the previous grouped expression indicated by that
number. For example @samp{\2} matches the second group expression. The order
of group expressions is determined by the position of their opening parenthesis
@samp{\(}.
+
+The alternation operator is @samp{\|}.
+
+The character @samp{^} only represents the beginning of a string when it
appears:
[EMAIL PROTECTED]
+
[EMAIL PROTECTED]
+At the beginning of a regular expression
+
[EMAIL PROTECTED] After an open-group, signified by
[EMAIL PROTECTED](}
+
[EMAIL PROTECTED] After the alternation operator @samp{\|}
+
[EMAIL PROTECTED] enumerate
+
+
+The character @samp{$} only represents the end of a string when it appears:
[EMAIL PROTECTED]
+
[EMAIL PROTECTED] At the end of a regular expression
+
[EMAIL PROTECTED] Before an close-group, signified by
[EMAIL PROTECTED])}
[EMAIL PROTECTED] Before the alternation operator @samp{\|}
+
[EMAIL PROTECTED] enumerate
+
+
[EMAIL PROTECTED], @samp{+} and @samp{?} are special at any point in a regular
expression except:
[EMAIL PROTECTED]
+
[EMAIL PROTECTED] At the beginning of a regular expression
+
[EMAIL PROTECTED] After an open-group, signified by
[EMAIL PROTECTED](}
[EMAIL PROTECTED] After the alternation operator @samp{\|}
+
[EMAIL PROTECTED] enumerate
+
+
+
+
+The longest possible match is returned; this applies to the regular expression
as a whole and (subject to this constraint) to subexpressions within groups.
+
+
[EMAIL PROTECTED] gnu-awk regular expression syntax
[EMAIL PROTECTED] @samp{gnu-awk} regular expression syntax
+
+
+The character @samp{.} matches any single character.
+
+
[EMAIL PROTECTED] @samp
+
[EMAIL PROTECTED] +
+indicates that the regular expression should match one or more occurrences of
the previous atom or regexp.
[EMAIL PROTECTED] ?
+indicates that the regular expression should match zero or one occurrence of
the previous atom or regexp.
[EMAIL PROTECTED] \+
+matches a @samp{+}
[EMAIL PROTECTED] \?
+matches a @samp{?}.
[EMAIL PROTECTED] table
+
+
+Bracket expressions are used to match ranges of characters. Bracket
expressions where the range is backward, for example @samp{[z-a]}, are invalid.
Within square brackets, @samp{\} can be used to quote the following character.
Character classes are supported; for example @samp{[[:digit:]]} will match a
single decimal digit.
+
+GNU extensions are supported:
[EMAIL PROTECTED]
+
[EMAIL PROTECTED] @samp{\w} matches a character within a word
+
[EMAIL PROTECTED] @samp{\W} matches a character which is not within a word
+
[EMAIL PROTECTED] @samp{\<} matches the beginning of a word
+
[EMAIL PROTECTED] @samp{\>} matches the end of a word
+
[EMAIL PROTECTED] @samp{\b} matches a word boundary
+
[EMAIL PROTECTED] @samp{\B} matches characters which are not a word boundary
+
[EMAIL PROTECTED] @samp{\`} matches the beginning of the whole input
+
[EMAIL PROTECTED] @samp{\'} matches the end of the whole input
+
[EMAIL PROTECTED] enumerate
+
+
+Grouping is performed with parentheses @samp{()}. An unmatched @samp{)}
matches just itself. A backslash followed by a digit acts as a back-reference
and matches the same thing as the previous grouped expression indicated by that
number. For example @samp{\2} matches the second group expression. The order
of group expressions is determined by the position of their opening parenthesis
@samp{(}.
+
+The alternation operator is @samp{|}.
+
+The characters @samp{^} and @samp{$} always represent the beginning and end of
a string respectively, except within square brackets. Within brackets,
@samp{^} can be used to invert the membership of the character class being
specified.
+
[EMAIL PROTECTED], @samp{+} and @samp{?} are special at any point in a regular
expression except:
[EMAIL PROTECTED]
+
[EMAIL PROTECTED] At the beginning of a regular expression
+
[EMAIL PROTECTED] After an open-group, signified by
[EMAIL PROTECTED](}
[EMAIL PROTECTED] After the alternation operator @samp{|}
+
[EMAIL PROTECTED] enumerate
+
+
+
+
+The longest possible match is returned; this applies to the regular expression
as a whole and (subject to this constraint) to subexpressions within groups.
+
+
[EMAIL PROTECTED] grep regular expression syntax
[EMAIL PROTECTED] @samp{grep} regular expression syntax
+
+
+The character @samp{.} matches any single character except newline.
+
+
[EMAIL PROTECTED] @samp
+
[EMAIL PROTECTED] \+
+indicates that the regular expression should match one or more occurrences of
the previous atom or regexp.
[EMAIL PROTECTED] \?
+indicates that the regular expression should match zero or one occurrence of
the previous atom or regexp.
[EMAIL PROTECTED] + and ?
+match themselves.
[EMAIL PROTECTED] table
+
+
+Bracket expressions are used to match ranges of characters. Bracket
expressions where the range is backward, for example @samp{[z-a]}, are ignored.
Within square brackets, @samp{\} is taken literally. Character classes are
supported; for example @samp{[[:digit:]]} will match a single decimal digit.
Non-matching lists @[EMAIL PROTECTED] do not ever match newline.
+
+GNU extensions are supported:
[EMAIL PROTECTED]
+
[EMAIL PROTECTED] @samp{\w} matches a character within a word
+
[EMAIL PROTECTED] @samp{\W} matches a character which is not within a word
+
[EMAIL PROTECTED] @samp{\<} matches the beginning of a word
+
[EMAIL PROTECTED] @samp{\>} matches the end of a word
+
[EMAIL PROTECTED] @samp{\b} matches a word boundary
+
[EMAIL PROTECTED] @samp{\B} matches characters which are not a word boundary
+
[EMAIL PROTECTED] @samp{\`} matches the beginning of the whole input
+
[EMAIL PROTECTED] @samp{\'} matches the end of the whole input
+
[EMAIL PROTECTED] enumerate
+
+
+Grouping is performed with backslashes followed by parentheses @samp{\(},
@samp{\)}. A backslash followed by a digit acts as a back-reference and
matches the same thing as the previous grouped expression indicated by that
number. For example @samp{\2} matches the second group expression. The order
of group expressions is determined by the position of their opening parenthesis
@samp{\(}.
+
+The alternation operator is @samp{\|}.
+
+The character @samp{^} only represents the beginning of a string when it
appears:
[EMAIL PROTECTED]
+
[EMAIL PROTECTED]
+At the beginning of a regular expression
+
[EMAIL PROTECTED] After an open-group, signified by
[EMAIL PROTECTED](}
+
[EMAIL PROTECTED] After a newline
+
[EMAIL PROTECTED] After the alternation operator @samp{\|}
+
[EMAIL PROTECTED] enumerate
+
+
+The character @samp{$} only represents the end of a string when it appears:
[EMAIL PROTECTED]
+
[EMAIL PROTECTED] At the end of a regular expression
+
[EMAIL PROTECTED] Before an close-group, signified by
[EMAIL PROTECTED])}
[EMAIL PROTECTED] Before a newline
+
[EMAIL PROTECTED] Before the alternation operator @samp{\|}
+
[EMAIL PROTECTED] enumerate
+
+
[EMAIL PROTECTED], @samp{\+} and @samp{\?} are special at any point in a
regular expression except:
[EMAIL PROTECTED]
+
[EMAIL PROTECTED] At the beginning of a regular expression
+
[EMAIL PROTECTED] After an open-group, signified by
[EMAIL PROTECTED](}
[EMAIL PROTECTED] After a newline
+
[EMAIL PROTECTED] After the alternation operator @samp{\|}
+
[EMAIL PROTECTED] enumerate
+
+
+Intervals are specified by @[EMAIL PROTECTED] and @[EMAIL PROTECTED] Invalid
intervals such as @[EMAIL PROTECTED] are not accepted.
+
+The longest possible match is returned; this applies to the regular expression
as a whole and (subject to this constraint) to subexpressions within groups.
+
+
[EMAIL PROTECTED] posix-awk regular expression syntax
[EMAIL PROTECTED] @samp{posix-awk} regular expression syntax
+
+
+The character @samp{.} matches any single character except the null character.
+
+
[EMAIL PROTECTED] @samp
+
[EMAIL PROTECTED] +
+indicates that the regular expression should match one or more occurrences of
the previous atom or regexp.
[EMAIL PROTECTED] ?
+indicates that the regular expression should match zero or one occurrence of
the previous atom or regexp.
[EMAIL PROTECTED] \+
+matches a @samp{+}
[EMAIL PROTECTED] \?
+matches a @samp{?}.
[EMAIL PROTECTED] table
+
+
+Bracket expressions are used to match ranges of characters. Bracket
expressions where the range is backward, for example @samp{[z-a]}, are invalid.
Within square brackets, @samp{\} can be used to quote the following character.
Character classes are supported; for example @samp{[[:digit:]]} will match a
single decimal digit.
+
+GNU extensions are not supported and so @samp{\w}, @samp{\W}, @samp{\<},
@samp{\>}, @samp{\b}, @samp{\B}, @samp{\`}, and @samp{\'} match @samp{w},
@samp{W}, @samp{<}, @samp{>}, @samp{b}, @samp{B}, @samp{`}, and @samp{'}
respectively.
+
+Grouping is performed with parentheses @samp{()}. An unmatched @samp{)}
matches just itself. A backslash followed by a digit acts as a back-reference
and matches the same thing as the previous grouped expression indicated by that
number. For example @samp{\2} matches the second group expression. The order
of group expressions is determined by the position of their opening parenthesis
@samp{(}.
+
+The alternation operator is @samp{|}.
+
+The characters @samp{^} and @samp{$} always represent the beginning and end of
a string respectively, except within square brackets. Within brackets,
@samp{^} can be used to invert the membership of the character class being
specified.
+
[EMAIL PROTECTED], @samp{+} and @samp{?} are special at any point in a regular
expression except the following places, where they are illegal:
[EMAIL PROTECTED]
+
[EMAIL PROTECTED] At the beginning of a regular expression
+
[EMAIL PROTECTED] After an open-group, signified by
[EMAIL PROTECTED](}
[EMAIL PROTECTED] After the alternation operator @samp{|}
+
[EMAIL PROTECTED] enumerate
+
+
+Intervals are specified by @[EMAIL PROTECTED] and @[EMAIL PROTECTED] Invalid
intervals such as @[EMAIL PROTECTED] are not accepted.
+
+The longest possible match is returned; this applies to the regular expression
as a whole and (subject to this constraint) to subexpressions within groups.
+
+
[EMAIL PROTECTED] posix-basic regular expression syntax
[EMAIL PROTECTED] @samp{posix-basic} regular expression syntax
+This is a synonym for ed.
[EMAIL PROTECTED] posix-egrep regular expression syntax
[EMAIL PROTECTED] @samp{posix-egrep} regular expression syntax
+
+
+The character @samp{.} matches any single character except newline.
+
+
[EMAIL PROTECTED] @samp
+
[EMAIL PROTECTED] +
+indicates that the regular expression should match one or more occurrences of
the previous atom or regexp.
[EMAIL PROTECTED] ?
+indicates that the regular expression should match zero or one occurrence of
the previous atom or regexp.
[EMAIL PROTECTED] \+
+matches a @samp{+}
[EMAIL PROTECTED] \?
+matches a @samp{?}.
[EMAIL PROTECTED] table
+
+
+Bracket expressions are used to match ranges of characters. Bracket
expressions where the range is backward, for example @samp{[z-a]}, are ignored.
Within square brackets, @samp{\} is taken literally. Character classes are
supported; for example @samp{[[:digit:]]} will match a single decimal digit.
Non-matching lists @[EMAIL PROTECTED] do not ever match newline.
+
+GNU extensions are supported:
[EMAIL PROTECTED]
+
[EMAIL PROTECTED] @samp{\w} matches a character within a word
+
[EMAIL PROTECTED] @samp{\W} matches a character which is not within a word
+
[EMAIL PROTECTED] @samp{\<} matches the beginning of a word
+
[EMAIL PROTECTED] @samp{\>} matches the end of a word
+
[EMAIL PROTECTED] @samp{\b} matches a word boundary
+
[EMAIL PROTECTED] @samp{\B} matches characters which are not a word boundary
+
[EMAIL PROTECTED] @samp{\`} matches the beginning of the whole input
+
[EMAIL PROTECTED] @samp{\'} matches the end of the whole input
+
[EMAIL PROTECTED] enumerate
+
+
+Grouping is performed with parentheses @samp{()}. A backslash followed by a
digit acts as a back-reference and matches the same thing as the previous
grouped expression indicated by that number. For example @samp{\2} matches the
second group expression. The order of group expressions is determined by the
position of their opening parenthesis @samp{(}.
+
+The alternation operator is @samp{|}.
+
+The characters @samp{^} and @samp{$} always represent the beginning and end of
a string respectively, except within square brackets. Within brackets,
@samp{^} can be used to invert the membership of the character class being
specified.
+
+The characters @samp{*}, @samp{+} and @samp{?} are special anywhere in a
regular expression.
+
+Intervals are specified by @[EMAIL PROTECTED] and @[EMAIL PROTECTED] Invalid
intervals are treated as literals, for example @[EMAIL PROTECTED] is treated as
@[EMAIL PROTECTED]
+
+The longest possible match is returned; this applies to the regular expression
as a whole and (subject to this constraint) to subexpressions within groups.
+
+
[EMAIL PROTECTED] posix-extended regular expression syntax
[EMAIL PROTECTED] @samp{posix-extended} regular expression syntax
+
+
+The character @samp{.} matches any single character except the null character.
+
+
[EMAIL PROTECTED] @samp
+
[EMAIL PROTECTED] +
+indicates that the regular expression should match one or more occurrences of
the previous atom or regexp.
[EMAIL PROTECTED] ?
+indicates that the regular expression should match zero or one occurrence of
the previous atom or regexp.
[EMAIL PROTECTED] \+
+matches a @samp{+}
[EMAIL PROTECTED] \?
+matches a @samp{?}.
[EMAIL PROTECTED] table
+
+
+Bracket expressions are used to match ranges of characters. Bracket
expressions where the range is backward, for example @samp{[z-a]}, are invalid.
Within square brackets, @samp{\} is taken literally. Character classes are
supported; for example @samp{[[:digit:]]} will match a single decimal digit.
+
+GNU extensions are supported:
[EMAIL PROTECTED]
+
[EMAIL PROTECTED] @samp{\w} matches a character within a word
+
[EMAIL PROTECTED] @samp{\W} matches a character which is not within a word
+
[EMAIL PROTECTED] @samp{\<} matches the beginning of a word
+
[EMAIL PROTECTED] @samp{\>} matches the end of a word
+
[EMAIL PROTECTED] @samp{\b} matches a word boundary
+
[EMAIL PROTECTED] @samp{\B} matches characters which are not a word boundary
+
[EMAIL PROTECTED] @samp{\`} matches the beginning of the whole input
+
[EMAIL PROTECTED] @samp{\'} matches the end of the whole input
+
[EMAIL PROTECTED] enumerate
+
+
+Grouping is performed with parentheses @samp{()}. An unmatched @samp{)}
matches just itself. A backslash followed by a digit acts as a back-reference
and matches the same thing as the previous grouped expression indicated by that
number. For example @samp{\2} matches the second group expression. The order
of group expressions is determined by the position of their opening parenthesis
@samp{(}.
+
+The alternation operator is @samp{|}.
+
+The characters @samp{^} and @samp{$} always represent the beginning and end of
a string respectively, except within square brackets. Within brackets,
@samp{^} can be used to invert the membership of the character class being
specified.
+
[EMAIL PROTECTED], @samp{+} and @samp{?} are special at any point in a regular
expression except the following places, where they are illegal:
[EMAIL PROTECTED]
+
[EMAIL PROTECTED] At the beginning of a regular expression
+
[EMAIL PROTECTED] After an open-group, signified by
[EMAIL PROTECTED](}
[EMAIL PROTECTED] After the alternation operator @samp{|}
+
[EMAIL PROTECTED] enumerate
+
+
+Intervals are specified by @[EMAIL PROTECTED] and @[EMAIL PROTECTED] Invalid
intervals such as @[EMAIL PROTECTED] are not accepted.
+
+The longest possible match is returned; this applies to the regular expression
as a whole and (subject to this constraint) to subexpressions within groups.
+
+
[EMAIL PROTECTED] posix-minimal-basic regular expression syntax
[EMAIL PROTECTED] @samp{posix-minimal-basic} regular expression syntax
+
+
+The character @samp{.} matches any single character except the null character.
+
+
+
+Bracket expressions are used to match ranges of characters. Bracket
expressions where the range is backward, for example @samp{[z-a]}, are invalid.
Within square brackets, @samp{\} is taken literally. Character classes are
supported; for example @samp{[[:digit:]]} will match a single decimal digit.
+
+GNU extensions are supported:
[EMAIL PROTECTED]
+
[EMAIL PROTECTED] @samp{\w} matches a character within a word
+
[EMAIL PROTECTED] @samp{\W} matches a character which is not within a word
+
[EMAIL PROTECTED] @samp{\<} matches the beginning of a word
+
[EMAIL PROTECTED] @samp{\>} matches the end of a word
+
[EMAIL PROTECTED] @samp{\b} matches a word boundary
+
[EMAIL PROTECTED] @samp{\B} matches characters which are not a word boundary
+
[EMAIL PROTECTED] @samp{\`} matches the beginning of the whole input
+
[EMAIL PROTECTED] @samp{\'} matches the end of the whole input
+
[EMAIL PROTECTED] enumerate
+
+
+Grouping is performed with backslashes followed by parentheses @samp{\(},
@samp{\)}. A backslash followed by a digit acts as a back-reference and
matches the same thing as the previous grouped expression indicated by that
number. For example @samp{\2} matches the second group expression. The order
of group expressions is determined by the position of their opening parenthesis
@samp{\(}.
+
+
+
+The character @samp{^} only represents the beginning of a string when it
appears:
[EMAIL PROTECTED]
+
[EMAIL PROTECTED]
+At the beginning of a regular expression
+
[EMAIL PROTECTED] After an open-group, signified by
[EMAIL PROTECTED](}
+
[EMAIL PROTECTED] enumerate
+
+
+The character @samp{$} only represents the end of a string when it appears:
[EMAIL PROTECTED]
+
[EMAIL PROTECTED] At the end of a regular expression
+
[EMAIL PROTECTED] Before an close-group, signified by
[EMAIL PROTECTED])}
[EMAIL PROTECTED] enumerate
+
+
+
+
+Intervals are specified by @[EMAIL PROTECTED] and @[EMAIL PROTECTED] Invalid
intervals such as @[EMAIL PROTECTED] are not accepted.
+
+The longest possible match is returned; this applies to the regular expression
as a whole and (subject to this constraint) to subexpressions within groups.
+
+
[EMAIL PROTECTED] sed regular expression syntax
[EMAIL PROTECTED] @samp{sed} regular expression syntax
+This is a synonym for ed.
\ No newline at end of file
