This is the built-in help made by Microsoft for the document 'about_operators', in PowerShell version 2 - as retrieved from
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TOPIC
about_Operators
SHORT DESCRIPTION
Describes the operators that are supported by Windows PowerShell.
LONG DESCRIPTION
An operator is a language element that you can use in a command or
expression. Windows PowerShell supports several types of operators to
help you manipulate values.
Arithmetic Operators
Use arithmetic operators (+, -, *, /, %) to calculate values in a command
or expression. With these operators, you can add, subtract, multiply, or
divide values, and calculate the remainder (modulus) of a division
operation.
You can also use arithmetic operators with strings, arrays, and hash
tables. The addition operator concatenates elements. The multiplication
operator returns the specified number of copies of each element.
For more information, see about_Arithmetic_Operators.
Assignment Operators
Use assignment operators (=, +=, -=, *=, /=, %=) to assign one or more
values to variables, to change the values in a variable, and to append
values to variables. You can also cast the variable as any Microsoft .NET
Framework data type, such as string or DateTime, or Process variable.
For more information, see about_Assignment_Operators.
Comparison Operators
Use comparison operators (-eq, -ne, -gt, -lt, -le, -ge) to compare values
and test conditions. For example, you can compare two string values to
determine whether they are equal.
The comparison operators include the match operators (-match, -notmatch)
to find patterns using regular expressions; the replace operator
(-replace), which uses regular expressions to change input values; and
the like operators (-like, -notlike), which find patterns using wildcard
characters (*).
They also include the bitwise operators (-bAND, -bOR, -bXOR, -bNOT) to
manipulate the bit patterns in values.
For more information, see about_Comparison_Operators
Logical Operators
Use logical operators (-and, -or, -xor, -not, !) to connect conditional
statements into a single complex conditional. For example, you can use a
logical -and operator to create an object filter with two different
conditions.
For more information, see about_Logical_Operators.
Redirection Operators
Use redirection operators (>, >>, 2>, 2>, and 2>&1) to send the output of
a command or expression to a text file. The redirection operators work
like the Out-File cmdlet (without parameters) but they also let you
redirect error output to specified files. You can also use the Tee-Object
cmdlet to redirect output.
For more information, see about_Redirection.
Split and Join Operators
The -split and -join operators divide and combine substrings. The -split
operator splits a string into substrings. The -join operator concatenates
multiple strings into a single string.
For more information, see about_Split and about_Join.
Type Operators
Use the type operators (-is, -isnot, -as) to find or change the .NET
Framework type of an object.
For more information, see about_Type_Operators.
Unary Operators
Use unary operators to increment or decrement variables or object
properties and to set integers to positive or negative numbers. For
example, to increment the variable $a from 9 to 10, you type $a++.
Special Operators
Use special operators to perform tasks that cannot be performed by the
other types of operators. For example, special operators allow you to
perform operations such as running commands and changing a value's data
type.
& Call operator
Description: Runs a command, script, or script block. Because the call
operator does not parse, it cannot interpret command parameters. The
call operator, also known as the "invocation operator, indicates that
the value it precedes is a command. This enables you to run commands
stored in variables and represented by strings. Examples:
& "new cmdlet"
$c = "get-executionpolicy"
& $c
. Property dereference operator
Description: Accesses the properties and methods of an object.
Examples:
$myString.length
$myString.substring(1,3)
. dot sourcing operator
Description: Runs a script so that the items in the script are part
of the calling scope. For more information, see about_Scope. Example:
. c:\scripts.sample.ps1
Note: The dot (.) symbol is also used as the parent directory symbol,
as in this example:
.\sample.ps1
This command runs the sample.ps1 script, but not as part of the
calling scope.
:: Static member operator
Description: Calls the static properties operator and methods of a .NET
Framework class. To find the static properties and methods of an
object, use the Static parameter of the Get-Member cmdlet. Example:
[datetime]::now
.. Range operator
Description: Represents the sequential integers in an integer array,
given an upper and lower boundary. Examples:
1..10
10..1
foreach ($a in 1..$max) {write-host $a}
-f Format operator
Description: Formats strings by using the format method of string
objects. Enter the format string on the left side of the operator
and the objects to be formatted on the right side of the operator.
Examples:
C:\PS> "{0} {1,-10} {2:N}" -f
C:\PS> 1,"hello",[math]::pi
1 hello 3.14
$( ) Subexpression operator
Description: Returns the result of one or more statements. For a
single result, returns a scalar. For multiple results, returns an
array. Examples:
$($x * 23)
$(Get-WMIObject win32_Directory)
@( ) Array subexpression operator
Description: Returns the result of one or more statements as an array.
If there is only one item, the array has only one member. Example:
@(Get-WMIObject win32_logicalDisk)
, operator
Description: As a binary operator, the comma creates an array. As a
unary operator, the comma creates an array with one member. Place the
comma before the member. Examples:
$myArray = 1,2,3
$SingleArray = ,1
SEE ALSO
about_Arithmetic_Operators
about_Assignment_Operators
about_Comparison_Operators
about_Logical_Operators
about_Type_Operators
about_Split
about_Join
about_Redirection