\
Escapes a regular expression special
character.
^
Signifies the start of a line.
When used immediately after an opening
brace, negates the character set inside the
brace.
[^abc]
matches any single character that is NOT one
of a, b or c
$
Signifies the end of a line.
^\d\d\d$
matches any string that is exactly 3 digits
long
(?!...)
Negative lookahead. Defines a
subexpression that must not be present.
(?!.*@example.com$).*
matches any string that
does not end with
@example.com
(?!alice).*
matches any string that does not start
with
alice
(?<!...)
Negative lookbehind. Defines a
subexpression that must not be present.
.*(?<!net)
matches any string that does not end with
net
Note that regex comparisons are not case sensitive.
For an example of regular expression usage, see the
CPL examples
section.
Cisco VCS Administrator Guide (X8.1.1)
Page 401 of 507
Reference material
Regular expressions