PowerShell cmdlets and functions can have parameters, and these parameters can have (shorter) alias names. One prominent example is the –ErrorAction common parameter which can also be accessed via its alias name -ea.
Parameter alias names are not auto-completed. You need to know them. Here is a script that can dump the parameter aliases for any PowerShell function or cmdlet:
#requires -Version 3 $command = 'Get-Process' (Get-Command $command).Parameters.Values | Select-Object -Property Name, Aliases