H3C Technologies H3C Intelligent Management Center - Manual (Page 134)

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13 Regular expressions
Overview
A regular expression is a sequence of characters that forms a search pattern for string matching. A
regular expression contains the following elements:
• Regular characters (letters and digits) with literal meanings.
• Metacharacters with special meanings.
Table 1 lists common metacharacters and their meanings.
Table 1 Metacharacters in a regular expression
Metacharacters Meaning Examples
^ Matches the beginning of a line.
"^display$" matches "display".
$ Matches the end of a line.
*
Matches the preceding character or
string zero, one, or multiple times.
"zo*" matches "z", "zo", and "zoo".
+
Matches the preceding character or
string one or multiple times.
"zo+" matches "zo" and "zoo", but not "z".
( ) Matches the string in the parentheses.
"(ABC)" matches "ABC".
"A(BC)+" matches "ABC" and "ABCBC".
?
Matches the preceding character or
string zero or one time.
"do(es)?" matches "do" and "does".
{n}
Matches the preceding character n
times. The number n must be a
nonnegative integer.
"fo{2}d" matches "food", but not "fod".
{n,}
Matches the preceding character n
times or more. The number n must be
a nonnegative integer.
"fo{2,}d" matches "food" and "foood", but not
"fod".
{n,m}
Matches the preceding character n to
m times or more. The numbers n and
m must be nonnegative integers and n
cannot be greater than m.
"fo{2,3}d" matches "food", and "foood", but not
"fod".
.
Matches any single character except
\n.
N/A
x|y Matches x or y. "m|pay" matches "m" and "pay". "(m|p)ay"
matches "may" and "pay".
[xyz] Matches a single character in the
brackets: x, y, or z. "a[xyz]" matches "ax", "ay", and "az".
[^xyz]
Matches a single character that is not
in the brackets. "a[^xyz]" matches "aa", "ab", and "az", but not
"ax", "ay", or "az".