Metacharacters
Table 5 on page 42 describes the metacharacters supported for regular expression
pattern-matching.
Table 5: Supported Regular Expression Metacharacters
DescriptionMetacharacter
Matches the beginning of the input string.
Alternatively, when used as the first character within brackets—[^ ]—matches
any number except the ones specified within the brackets.
^
Matches the end of the input string.$
Matches any single character, including white space..
Matches 0 or more sequences of the immediately previous character or
pattern.
*
Matches 1 or more sequences of the immediately previous character or
pattern.
+
Matches 0 or 1 sequence of the immediately previous character or pattern.?
Specifies patterns for multiple use when followed by one of the multiplier
metacharacters: asterisk *, plus sign +, or question mark ?
()
Matches any enclosed character; specifies a range of single characters.[ ]
Used within brackets to specify a range of AS or community numbers.– (hyphen)
Matches a ^, a $, a comma, a space, a {, or a }. Placed on either side of a
string to specify a literal and disallow substring matching. Numerals enclosed
by underscores can be preceded or followed by any of the characters listed
above.
_ (underscore)
Matches characters on either side of the metacharacter; logical OR.|
Using Metacharacters as Literal Tokens
You can remove the special meaning of a metacharacter by preceding it with a
backslash (\). Such a construction denotes that the metacharacter is not treated as a
metacharacter for that regular expression. It is simply a character or token with no
special meaning, just as a numeral has no special meaning. The backslash applies
only to the character immediately following it in the regular expression.
On the E Series router, you are likely to do this only for the parentheses characters,
( or ). BGP indicates a segment of an AS path that is of type AS-confed-set or
AS-confed-seq by enclosing that segment within parentheses.
42 ■ Overview
JUNOSe 11.1.x System Basics Configuration Guide
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