ErrorAction SilentlyContinue

Sometimes you run a command to "check" something -- and it throws an error that is completely unwanted.

e.g. you type dir abc ... you don't expect an error!

> dir abc
dir : Cannot find path 'C:\temp\abc' because it does not exist.
At line:1 char:1
+ dir abc
+ ~~~~~~~
    + CategoryInfo          : ObjectNotFound: (C:\temp\abc:String) [Get-Child
Item], ItemNotFoundException
    + FullyQualifiedErrorId : PathNotFound,Microsoft.PowerShell.Commands.GetChildItemCommand

Add the parameter: -ErrorAction SilentlyContinue to avoid this behaviour:

dir abc -ErrorAction SilentlyContinue

Using the $ErrorActionPreference variable =v "SilentlyContinue"

Instead of setting the behaviour on each command, you can set it for the entire session, but using the preference variable: $ErrorActionPreference

This defaults to having a value of Continue (meaning -- display an error but continue processing.)

You can set it to any value you want. e.g.

$ErrorActionPreference = "SilentlyContinue"
dir abc

(No output, since there was no such file, and no error, due to the SilentlyContinue preference)