Coyote Point Systems Equalizer GX Series, Руководство администратора

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How to Use Regular Expressions
Creating a Bracket Expression
A bracket expression is a list of characters enclosed in brackets ([...]). It normally matches any
single character from the list. If the list begins with ^, it matches any single character not from
the rest of the list. Two characters in a list that are separated by '-' indicates the full range of
characters between those two (inclusive) in the collating sequence; for example, '[0-9]' in ASCII
matches any decimal digit. It is illegal for two ranges to share an endpoint; for example, 'a-c-e'.
Ranges are very collating-sequence-dependent, and portable programs should avoid relying on
them.
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To include a literal ']' in the list, make it the first character (following an optional '^').
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To include a literal '-', make it the first or last character, or the second endpoint of a range.
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To use a literal '-' as the first endpoint of a range, enclose it in '[.' and '.]' to make it a col-
lating element (see below).
With the exception of these and some combinations using '[' (see next paragraphs), all other
special characters, including '\', lose their special significance within a bracket expression.
Within a bracket expression, a collating element (a character, a multi-character sequence that
collates as if it were a single character, or a collating-sequence name for either) enclosed in '[.'
and '.]' stands for the sequence of characters of that collating element. The sequence is a single
element of the bracket expression's list. A bracket expression containing a multi-character
collating element can thus match more than one character; e.g., if the collating sequence includes
a 'ch' collating element, then the real expression '[[.ch.]]*c' matches the first five characters of
'chchcc'.
Within a bracket expression, a collating element enclosed in '[' and `]' is an equivalence class,
representing the sequences of characters of all collating elements equivalent to that one,
including itself. (If there are no other equivalent collating elements, the treatment is as if the
enclosing delimiters were '[.' and '.]'.) For example, if 'x' and 'y' are the members of an
equivalence class, then '[[x]]', '[[y]]', and '[xy]' are all synonymous. An equivalence class may
not be an end-point of a range.
Within a bracket expression, the name of a character class enclosed in '[:' and ':]' stands for the
list of all characters belonging to that class.
There are two special cases of bracket expressions: the bracket expressions '[[:<:]]' and '[[:>:]]
' match the null string at the beginning and end of a word respectively. A word is defined as a
sequence of word characters that is neither preceded nor followed by word characters. A word
character is an alnum character (as defined by ctype(3)) or an underscore. This is an extension,
compatible with but not specified by IEEE Std 1003.2 (''POSIX.2''), and should be used with
caution in software intended to be portable to other systems.
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