PowerShell: Controlling Cmdlet parameters
PowerShell allows for inline parameter control for some of its cmdlet parameters. Based upon commandline and/or inputfile content you might want to turm some of the cmdlet parameters on or off.
For example: scripts manipulating files will often use the Get-ChildItem cmdlet in combination with the -recurse parameter, but not allways the subfolder files are required. Instead off having multiple Get-ChildItem commandlines (each with their own set of parameters) a single line might be possible.
The following examples use the Get-ChildItem cmdlet to show what I mean.
The command in figure below will display all *.tmp files in the current folder and its subfolders.
By extending -recurse with :$false recursive lookup will be turned off.
On the otherhand, replacing $false with $true will turn recursive lookup on again.
So using a boolean variable we can turn recursive lookup on or off from within the script (-recurse:$RecurseOnOff). And of course this method also works for other parameters.
And it does get stranger….. in some occasions you can also reverse the default action of a parameter. Hence the following figure.
The 1st command will show all files with exception of the *.tmp files. By appending :$false to -exclude, we turn -exclude into -include as demonstrated by the 2nd command.
This form of parameter manipulation offers a scala of possibilities. Using script parameters to control cmdlet behaviour can both decrease script size and complexity.
Have fun experimenting with this little trick
