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PowerShell ElseIf Statement

Introduction to PowerShell's Else If Logic

PowerShell's 'ElseIf' statement comes under the umbrella of flow control.  Once you master the basic 'If' construction then you can increase the scope of your script by appending, 'Else' and 'ElseIf' to logic statements.

Topics for PowerShell's ElseIf Statement

• Begin With The Plain 'If' Statement
• Example 1: Plain PowerShell If
• Example 2: PowerShell ElseIf
• Example 3: PowerShell ElseIf and Plain Else
• Example 4: Check If a Service is Installed and Working
• Example 5: PowerShell ElseIf Help File
• PowerShell If -or
• Summary of PowerShell's ElseIf Construction

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Begin With The Plain 'If' Statement

Let us get started by mastering PowerShell's basic 'If' construction.  All that you need is a condition or test, followed by the block command payload.

Note in passing that PowerShell employs different types of bracket for each component, the (parenthesis style of bracket are for the first part, namely the condition), while {braces are for the block command}.

Here is a different explanation of the same 'If' construction:

Summary:  The PowerShell 'If' conditionally executes what's inside the {curly brackets}, depending on the truth of the test expression.

Example 1: Plain PowerShell 'If'

Learning Points

Note 1:  Separate the If statement into two components: if (test) and {what to do}, then study each component of the PowerShell construction.

Note 2:  Avoid over-think; remember that there is no 'Then' in a PowerShell 'If' statement.  Incidentally, for those familiar with VBScript there is no endif in PowerShell.

Example 2: PowerShell ElseIf

Let us extend my trivial 'If' example by introducing an 'ElseIf' statement.  Incidentally, while ElseIf is not case sensitive, it does highlight the two words 'Else' and 'if'.

Note 3: Do check the logic of each line.  -gt is PowerShell's way of saying 'Greater than', and -lt means 'Less than'.

PowerShell Else If

I cannot get Else If, to work; what I find is that when there is a space between the Else and If it does not work for me.  What what happens is I get an error message: 'Missing block statement'.

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Example 3: PowerShell ElseIf and Plain Else

It's good practice to add a final Else statement.  This catch-all will check for anything that slips through your ElseIf logic.  For example, what if the value of $Number was precisely zero?

Example 4: Check If a Service is Installed and Working

Here is a real-life example of PowerShell ElseIf script, it uses the 'Display' property of the Windows spooler service.

Note 4:  In addition to that final 'Else', this example uses multiple ElseIfs, however, for scripts that need even more complex logic I prefer 'PowerShell's Switch'.

Note 5:  See more on -ErrorAction SilentlyContinue

Researching PowerShell's Else If Logic

For more information refer to PowerShell's built-in About_IF file

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Example 5: PowerShell ElseIf Help File

This example has an important task, and that is to check that we have the name of an actual file.  Remember the second (test statement) followed by a second {Block Script}.

Learning Points

Note 6:  The advantage of ElseIf over plain Else, is that we can introduce more tests.  In the above example we use ElseIf to check if the length of the file is less than 1.  To activate the 'ElseIf' block, set $File to a non-existent file for example
$File = Get-Help about_ifxx.

Note 7: To trigger the final 'Else', try changing:
$File = Get-Help about_if
to
$File = Get-Help about_scope

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Summary of PowerShell's ElseIf Construction

One of the oldest, and one of the best statements for filtering data is the 'If' clause.  Nevertheless it's always worth a refresher on the basic 'If' statement, before progressing to the more versitile 'ElseIf'.  The secret of understanding PowerShell's impementation of If and ElseIf is to pay close attention to the style bracket.  ElseIf (parenthesis for the test) and {braces for the action}. 

See more Windows PowerShell examples

• PowerShell Home  • PowerShell If Statement  • PowerShell ElseIf  • PowerShell If -Not

• PowerShell comparison operators  • PowerShell If -And  • PowerShell If -Or

• Where Filter   • Loops  • Brackets  • -Match  • Switch  • Conditional Operators

Please email me if you have a better example script. Also please report any factual mistakes, grammatical errors or broken links, I will be happy to correct the fault.

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Author: Guy Thomas Copyright © 1999-2012 Computer Performance LTD All rights reserved. Please report a broken link, or an error to: