Here I offer the reader a bit of output from the Microsoft Windows ( .NET ) Powershell. Powershell is available for windows users to download for no cost, as a facility for interfacing with many .NET functions, as well as some typical Windows Shell (cmd.exe) functions; some interesting enhancements to the functionality of The OS and available .NET Framework components which may be able to do some heavy lifting, as its said, for the user in a fraction of the time and effort which may be required through other means.
Please note that it is for the express purpose of DEMONSTRATION ONLY, so the reader might make his or her own decisions about the subject, as this author makes no claim here regarding the quality of the software itself or the operation thereof, his fascination with the software notwithstanding. WordPress Center .net encourages you, the reader, to develop your own opinions and share your feelings in the comments below. We hot that such texts are educational, insightful, and balanced.
as output, verbatim from Windows PowerShell™, the following shows a query instance of “get-help about_*”, where the last few cmdlet items are shown, then I specifiy precisely “get-help about_regular”, where Powershell was intuitive enough to display that which I wanted: more information on the available Windows .Net Powershell Regular Expression syntax
about_property HelpFile Using object propertie...
about_provider HelpFile Windows PowerShell pro...
about_pssnapins HelpFile A Windows PowerShell s...
about_quoting_rules HelpFile Rules for setting the ...
about_redirection HelpFile Redirecting output fro...
about_ref HelpFile How to create and use ...
about_regular_expression HelpFile Using regular expressi...
about_reserved_words HelpFile Words in the Windows P...
about_scope HelpFile The visibility a funct...
about_script_block HelpFile Grouping statements an...
about_shell_variable HelpFile Variables that are cre...
about_signing HelpFile Describes the Windows ...
about_special_characters HelpFile The special characters...
about_switch HelpFile Using a switch to hand...
about_system_state HelpFile Data maintained by the...
about_types HelpFile Extending the .NET typ...
about_where HelpFile Filter objects based o...
about_while HelpFile A language statement f...
about_wildcard HelpFile Using wildcards in Cmd...
SEE ALSO
For information about the match comparison operator, enter the
following command at the PowerShell command prompt:
help about_comparison_operators
See the MSDN Documentation on Regular Expression Language Elements
PS C:> get-help about_regular
TOPIC Regular expressions
SHORT DESCRIPTION
Using regular expressions in Cmdlet parameters in the Windows PowerShell
LONG DESCRIPTION
PowerShell supports a number of the regular expression characters:
FormatLogicExample
-------- ------------------------------- -----------------------
value Matches exact characters "book" -match "oo"
anywhere in the original value
. Matches any single character "copy" -match "c..y"
[value] Matches at least one of the "big" -match "b[iou]g"
characters in the brackets
[range] Matches at least one of the "and" -match "[a-e]nd"
characters within the range.
The Use of a hyphen (-) allows
specification of contiguous
character.
[^] Matches any character except "and" -match "[^brt]nd"
those in brackets
^ Matches the beginning "book" -match "^bo"
characters
$ Matches the end characters "book" -match "ok$"
* Matches zero or more instances "baggy" -match "g*"
of the preceding character
? Matches zero or one instance "baggy" -match "g?"
of the preceding character
Matches the character that "Try$" -match "Try$"
follows as an escaped character
-------- ------------------------------- -----------------------
p{name} Matches any character in the "abcd defg" -match "p{Ll}+"
named character class specified
by {name}. Supported names are
Unicode groups and block
ranges. For example, Ll, Nd,
Z, IsGreek, IsBoxDrawing.
P{name} Matches text not included in 1234 -match "P{Ll}+"
groups and block ranges
specified in {name}.
w Matches any word character. "abcd defg" -match "w+"
Equivalent to the Unicode (this matches abcd)
character categories [p{Ll}
p{Lu}p{Lt}p{Lo}p{Nd}p{Pc}].
If ECMAScript-compliant behavior
is specified with the ECMAScript
option, w is equivalent to
[a-zA-Z_0-9].
W Matches any nonword character. "abcd defg" -match "W+"
Equivalent to the Unicode (This matches the space)
categories [^p{Ll}p{Lu}p{Lt}
p{Lo}p{Nd}p{Pc}].
s Matches any white-space "abcd defg" -match "s+"
character. Equivalent to the
Unicode character categories
[fnrtvx85p{Z}].
S Matches any non-white-space "abcd defg" -match "S+"
character. Equivalent to the
Unicode character categories
[^fnrtvx85p{Z}].
d Matches any decimal digit. 12345 -match "d+"
Equivalent to p{Nd} for
Unicode and [0-9] for non-
Unicode behavior.
D Matches any nondigit. "abcd" -match "D+"
Equivalent to P{Nd} for
Unicode and [^0-9] for non-
Unicode behavior.
PowerShell supports the quantifiers available in .NET regular expressions, The following are some examples of quantifiers in Powershell:
FormatLogic Example
-------- ------------------------------- -----------------------
* Specifies zero or more matches; "abc" -match "w*"
for example, w* or (abc)*.
Equivalent to {0,}.
+ Matches repeating instances of "xyxyxy" -match "xy+"
the preceding characters
? Specifies zero or one matches; "abc" -match "w?"
for example, w? or (abc)?.
Equivalent to {0,1}.
{n} Specifies exactly n matches; "abc" -match "w{2}"
for example, (pizza){2}.
{n,} Specifies at least n matches; "abc" -match "w{2,}"
for example, (abc){2,}.
{n,m} Specifies at least n, but no "abc" -match "w{2,3}"
more than m, matches.
All of the comparisons shown in the table above evaluate to true.
Note that the escape character for regular expressions is different than that of the PowerShell. The character escape for regular expressions is the backslash{1}.
{1}Backslash, aka. Reverse Solidus: [ U+005C ] : Note. Whenever you see a Unicode character represented as such (e.g. usually leading zeros in an alphanumeric sequence of 2-6 numbers), if a visible character exists for that code, that character can be represented as a Numerical Character Reference by replacing the “U+” part with &#x (“amp-hash-X”/ “amp-pound-X”), the-code (5C here because we can omit leading zeros) and a semi-colon [ ; ] indicates the end of the NCR so &#x 5c ; is rendered as \
SEE ALSO For information about the match comparison operator, enter the following command at the PowerShell command prompt:
help about_comparison_operators
See the MSDN Documentation on Regular Expression Language Elements
†Powershell is a Microsoft .NET thing which means so it’s also related to C# (the relative minor of E major). Any time you get to learn something from Hey Scripting Guy is also a bonus! Maybe it’s time to take Shia LaBeouf’s advice: “Do it!”
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