Supported Regular Expressions Syntax

Privilege Management for Windows can control applications at a granular level by using regular expression syntax. Privilege Management for Windows uses the ATL regular expression library CAtlRegExp. Below is a summary of the regular expression syntax used by this library.

Metacharacter

Meaning

Example

Any character except [\^$.|?*+()

All characters except the listed special characters match a single instance of themselves. To match one of these listed characters use a backslash escape character (see below).

"abc" matches "abc"

\ (backslash)

Escape character: interpret the next character literally.

"a\+b" matches "a+b"

. (dot)

Matches any single character.

"a.b" matches "aab", "abb" or "acb", etc.

[ ]

Indicates a character class. Matches any character inside the brackets (for example, [abc] matches "a", "b", and "c").

"[abc]" matches "a", "b", or "c"

^ (caret)

If this metacharacter occurs at the start of a character class, it negates the character class. A negated character class matches any character except those inside the brackets (for example, [^abc] matches all characters except "a", "b", and "c").

If ^ is at the beginning of the regular expression, it matches the beginning of the input (for example, ^[abc] will only match input that begins with "a", "b", or "c").

"[^abc]" matches all characters except "a", "b", and "c"

- (minus character)

In a character class, indicates a range of characters (for example, [0-9] matches any of the digits "0" through "9").

"[0-9]" matches any of the digits "0" through "9"

?

Indicates that the preceding expression is optional: it matches once or not at all (for example, [0-9][0-9]? matches "2" and "12").

"ab?c" matches "ac" or "abc"

+

Indicates that the preceding expression matches one or more times (for example, [0-9]+ matches "1", "13", "666", and so on).

"ab+c" matches "abc" and "abbc", "abbbc", etc.

* (asterisk)

Indicates that the preceding expression matches zero or more times

"ab*c" matches "ac" and "abc", "abbc", etc.

| (vertical pipe)

Alternation operator: separates two expressions, exactly one of which matches.

"a|b" matches "a" or "b"

??, +?, *?

Non-greedy versions of ?, +, and *. These match as little as possible, unlike the greedy versions which match as much as possible. Example: given the input "<abc><def>", <.*?> matches "<abc>" while <.*> matches "<abc><def>".

Given the input "<abc><def>", <.*?> matches "<abc>" while <.*> matches "<abc><def>".

( )

Grouping operator. Example: (\d+,)*\d+ matches a list of numbers separated by commas (such as "1" or "1,23,456").

"(One)|(Two)" matches "One" or "Two"

{ }

Indicates a match group. The actual text in the input that matches the expression inside the braces can be retrieved through the CAtlREMatchContext object.

 

\

Escape character: interpret the next character literally (for example, [0-9]+ matches one or more digits, but [0-9]\+ matches a digit followed by a plus character). Also used for abbreviations (such as \a for any alphanumeric character; see table below).

If \ is followed by a number n, it matches the nth match group (starting from 0). Example: <{.*?}>.*?</\0> matches "<head>Contents</head>".

Note that in C++ string literals, two backslashes must be used: "\\+", "\\a", "<{.*?}>.*?</\\0>".

<{.*?}>.*?</\0> matches "<head>Contents</head>"

$

At the end of a regular expression, this character matches the end of the input. Example: [0-9]$ matches a digit at the end of the input.

[0-9]$ matches a digit at the end of the input

|

Alternation operator: separates two expressions, exactly one of which matches (for example, T|the matches "The" or "the").

T|the matches "The" or "the")

!

Negation operator: the expression following ! does not match the input. Example: a!b matches "a" not followed by "b".

a!b matches "a" not followed by "b"