An if statement tests for a condition and takes action if the condition is true, but what if we want to do something if the condition is false? This is where else can be used:

$myVar = 2    
if($myVar -lt 0) {
  Write-Host "A negative number"
} else {
  Write-Host "A positive number"
}

The above example uses else after the initial if statement body. Curly braces after the else defines another body that contains the code to be executed if the condition is false.

else captures all other scenarios not met by your if statement. We can now define specific behaviors based on a true or false condition.

Depending on our situation, we may need to account for multiple conditions at a specific point in our code. This is where we could utilize the elseif conditional statement:

$myVar = 2    
if ($myVar -lt 0) {
  Write-Host "A negative number"
} elseif ($myVar -gt 0) {
  Write-Host "A positive number"
} else {
  Write-Host "Zero"
}

This example has two conditions to check. If the first condition, $myVar -lt 0, is false, the script moves on to the elseif with another condition in parentheses. If the second condition, $myVar -gt 0, is true, the code inside the body is run. The else body is executed if both conditions are false.

We can add as many elseif statements to an if statement as long as an else statement remains the final statement.