about_Logical_Operators

Applies To: Windows PowerShell 2.0

TOPIC
    about_Logical_Operators

SHORT DESCRIPTION
    Describes the operators that connect statements in Windows PowerShell.


LONG DESCRIPTION
    The Windows 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))

 
    Windows PowerShell supports the following logical operators.
 

        Operator  Description                      Example
        --------  ------------------------------   ------------------------
        -and      Logical and. TRUE only when      (1 -eq 1) -and (1 -eq 2) 
                  both statements are TRUE.         False

 
        -or       Logical or. TRUE when either     (1 -eq 1) -or (1 -eq 2) 
                  or both statements are TRUE.     True
 

        -xor      Logical exclusive or. TRUE       (1 -eq 1) -xor (2 -eq 2)
                  only when one of the statements  False 
                  is TRUE and the other is FALSE.
 
  
        -not      Logical not. Negates the         -not (1 -eq 1)
                  statement that follows it.       False

 
        !         Logical not. Negates the         !(1 -eq 1)
                  statement that follows it.       False
                  (Same as -not) 
 
 
    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:


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

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


    The Windows 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.


SEE ALSO
    about_Operators
    Compare-Object
    about_Comparison_operators
    about_If