Visara Master Console Center Scripting Guide - Manual (Page 64)

Chapter 4 Regular Expressions
Scripting Guide 64
Special Characters in Regular Expressions
Table 12. Regular Expressions, Special Characters describes the various
special characters that may be used in regular expressions. The
characters are special — except in bracket expressions or following a
backslash.
Character Description
. A period matches any single character.
\ When placed before a special character, a backslash nullifies
that special character. This allows searches for a character
that would otherwise be special (such as a period).
^ A circumflex matches the beginning of the line. The
circumflex is special when used as an anchor or as the first
character of a bracket expression.
$ A dollar sign matches the end of the line.
[ ] Brackets match any single instance of the characters inside
the brackets. Ranges can be specified, for instance, A-F. If
the first character after the open bracket is a circumflex, the
search is negated—matches any character not in the list. For
example, G-Z if you specified A-F. If a dash is to be matched
as a regular character, make it the first or last character in
the list.
It is not valid to use a left brace that is not part of an interval
expression (of course, quoting with a backslash removes such
invalidity).
( ) Parentheses form a subexpression. Up to nine
subexpressions are allowed in a regular expression; they may
be nested.
Outside a bracket expression, do not use a left parenthesis
unless it is preceded with a backslash and quoted “\(”.
To search for the string “()”, use the quoted form by preceding
with a backslash “\()”.
* 1 An asterisk matches zero or more occurrences of the
previous character, bracket, or subexpression—depending on
what precedes the asterisk.
+ 1 A plus sign matches one or more occurrences of the previous
character, bracket, or subexpression—depending on what
precedes the plus sign.
? 1 A question mark matches exactly zero or one occurrences of
the previous character, bracket, or subexpression—depending
on what precedes the question mark.
{n} 1 Brackets match exactly n occurrences of the previous
character, bracket, or subexpression—depending on what
precedes the {n}.
{n,m} {n,} matches n or more. {,m} matches m or less. {n,m} matches
n to m occurrences. Replace n and m with numbers specifying