Cisco Cisco Email Security Appliance C160 Guía Del Usuario
11-29
Cisco IronPort AsyncOS 7.5 for Email Configuration Guide
OL-25136-01
Chapter 11 Data Loss Prevention
Backslash special
characters (
characters (
\
)
The backslash character escapes special characters.
Thus the sequence
Thus the sequence
\.
only matches a literal period,
the sequence
\$
only matches a literal dollar sign, and
the sequence
\^
only matches a literal caret symbol.
The backslash character also begins tokens, such as
\d
.
Important Note: The backslash is also a special
escape character for the parser. As a result, if you
want to include a backslash in your regular
expression, you must use two backslashes — so that
after parsing, only one “real” backslash remains,
which is then passed to the regular expression system.
escape character for the parser. As a result, if you
want to include a backslash in your regular
expression, you must use two backslashes — so that
after parsing, only one “real” backslash remains,
which is then passed to the regular expression system.
\d
Token that matches a digit (
0
-
9
). To match more than
one digit, enter an integer in
{}
to define the length of
the number.
For example,
\d
matches only a single digit such as
5
,
but not
55
. Using
\d{2}
matches a number consisting
of two digits, such as
55
, but not
5
.
Number of repetitions
{min,max}
The regular expression notation that indicates the
number of repetitions of the previous token is
supported.
number of repetitions of the previous token is
supported.
For example, the expression “
\d{8}
” matches
12345678
and
11223344
but not
8
.
Or (
|
)
Alternation, or the “or” operator. If A and B are
regular expressions, the expression “
regular expressions, the expression “
A|B
” will match
any string that matches either “A” or “B.” Can be used
to combine number patterns in a regular expression.
to combine number patterns in a regular expression.
For example, the expression “
foo|bar
” will match
either
foo
or
bar
, but not
foobar
.
Table 11-2
Regular Expression in Classifiers