10
Characters Meaning Examples
\N
Matches the preceding strings in
parentheses, with the Nth string
repeated once.
"(string)\1" matches a string containing
"stringstring".
"(string1)(string2)\2" matches a string containing
"string1string2string2".
"(string1)(string2)\1\2" matches a string
containing " string1string2string1string2".
[ ]
Matches a single character in the
brackets.
"[16A]" matches a string containing 1, 6, or A;
"[1-36A]" matches a string containing 1, 2, 3, 6, or
A (- is a hyphen).
To match the character "]", put it immediately after
"[", for example, []abc]. There is no such limit on
"[".
[^]
Matches a single character that is not
in the brackets.
"[^16A]" matches a string that contains one or
more characters except for 1, 6, or A, such as
"abc". A match can also contain 1, 6, or A (such as
"m16"), but it cannot contain these three
characters only (such as 1, 16, or 16A).
{n}
Matches the preceding character n
times. The number n must be a
nonnegative integer.
"o{2}" matches "food", but not "Bob".
{n,}
Matches the preceding character n
times or more. The number n must be
a nonnegative integer.
"o{2,}" matches "foooood", but not "Bob".
{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.
" o{1,3}" matches "fod", "food", and "foooood", but
not "fd".
\<
Matches a string that starts with the
pattern following \<. A string that
contains the pattern is also a match if
the characters preceding the pattern
are not digits, letters, or underscores.
"\<do" matches "domain" and "doa".
\>
Matches a string that ends with the
pattern preceding \>. A string that
contains the pattern is also a match if
the characters following the pattern
are not digits, letters, or underscores.
"do\>" matches "undo" and "cdo".
\b
Matches a word that starts with the
pattern following \b or ends with the
pattern preceding \b.
"er\b" matches "never", but not "verb" or "erase".
"\ber" matches "erase", but not "verb" or "never".
\B
Matches a word that contains the
pattern but does not start or end with
the pattern.
"er\B" matches "verb", but not "never" or "erase".
\w
Same as [A-Za-z0-9_], matches a
digit, letter, or underscore.
"v\w" matches "vlan" and "service".
\W
Same as [^A-Za-z0-9_], matches a
character that is not a digit, letter, or
underscore.
"\Wa" matches "-a", but not "2a" or "ba".
\
Escape character. If a special
character listed in this table follows \,
the specific meaning of the character
is removed.
"\\" matches a string containing "\", "\^" matches a
string containing "^", and "\\b" matches a string
containing "\b".