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PowerShell 6 Logical Operators

Straight from Microsoft

SHORT DESCRIPTION

Describes the operators that connect statements in PowerShell.

LONG DESCRIPTION

The PowerShell logical operators connect expressions and statements, allowing you to use a single expression to test for multiple conditions.

For example, the following statement uses the and operator and the or operator to connect three conditional statements. The statement is true only when the value of $a is greater than the value of $b, and either $a or $b is less than 20.

($a -gt $b) -and (($a -lt 20) -or ($b -lt 20))

PowerShell supports the following logical operators.

OperatorDescriptionExample
-andLogical AND. TRUE when both(1 -eq 1) -and (1 -eq 2)
statements are TRUE.False
-orLogical OR. TRUE when either(1 -eq 1) -or (1 -eq 2)
statement is TRUE.True
-xorLogical EXCLUSIVE OR. TRUE when(1 -eq 1) -xor (2 -eq 2)
only one statement is TRUEFalse
-notLogical not. Negates the statement-not (1 -eq 1)
that follows.False
!Same as -not!(1 -eq 1)
False

Note:

The previous examples also use the equal to comparison operator -eq. For more information, see about_Comparison_Operators. The examples also use the Boolean values of integers. The integer 0 has a value of FALSE. All other integers have a value of TRUE.

The syntax of the logical operators is as follows:Copy

<statement> {-AND | -OR | -XOR} <statement>
{! | -NOT} <statement>

Statements that use the logical operators return Boolean (TRUE or FALSE) values.

The PowerShell logical operators evaluate only the statements required to determine the truth value of the statement. If the left operand in a statement that contains the and operator is FALSE, the right operand is not evaluated. If the left operand in a statement that contains the or statement is TRUE, the right operand is not evaluated. As a result, you can use these statements in the same way that you would use the If statement.

Remote Logoff Windows User

I ran into an issue were my RDP session go corrupted on a test server. I couldn’t logoff. I found this page that tells you how to force a logoff through PowerShell.

# Username to logoff
$userName = 'administrator'
# Get the session id from the server.  In this case the Server ID is 'DC'
$sessionId = ((quser /server:DC | Where-Object { $_ -match $userName }) -split ' +')[2]
# Display the session
$sessionId
# Logoff the Session ID from server DC
logoff $sessionId /server:DC

If you think hard about this you could put this into a script. Just don’t call it ‘logoff.ps1’ since that is a reserved keyword in PowerShell.