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I have some code:
$foo = someFunction This outputs a warning message which I want to redirect to $null:
$foo = someFunction > $null The problem is that when I do this, while successfully supressing the warning message, it also has the negative side-effect of NOT populating $foo with the result of the function.
How do I redirect the warning to $null, but still keep $foo populated?
Also, how do you redirect both standard output and standard error to null? (In Linux, it's 2>&1.)
890
asked May 04 '11 09:05
There are two PowerShell operators you can use to redirect output: > and >> . The > operator is equivalent to Out-File while >> is equivalent to Out-File -Append . The redirection operators have other uses like redirecting error or verbose output streams.
For example to capture only verbose output you can run the command as a subexpression. When run this outputs the error and warning objects to console but the verbose objects are saved into $VerboseOnly and the output objects are saved into $OutputOnly.
$null is an automatic variable in PowerShell used to represent NULL. You can assign it to variables, use it in comparisons and use it as a place holder for NULL in a collection. PowerShell treats $null as an object with a value of NULL. This is different than what you may expect if you come from another language.
I'd prefer this way to redirect standard output (native PowerShell)...
($foo = someFunction) | out-null But this works too:
($foo = someFunction) > $null To redirect just standard error after defining $foo with result of "someFunction", do
($foo = someFunction) 2> $null This is effectively the same as mentioned above.
Or to redirect any standard error messages from "someFunction" and then defining $foo with the result:
$foo = (someFunction 2> $null) To redirect both you have a few options:
2>&1>$null 2>&1 | out-null This should work.
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