How to escape characters inside of a parameter in Powershell?

Question

This is a simplified version of my function:

function DetectLocalUser($localGroup, $members) { $result = net localgroup "$localGroup" #$members= $members.Replace("\","\\") if ($result -match $members) { return $true } else { return $false } }

To invoke the function I use this example (Typical values I am going to receive):

DETECTLocalUser "test" "iis apppool\userapi"

The parameters are not controlled by me. If they were I would escape directly the second parameter "iis apppool\\userapi"

On execution I have a problem with the \ in the parameter. The exact error is:

parsing "iis apppool\icisapi" - Unrecognized escape sequence \i. At C:\k\a.ps1:6 char:9 + if ($result -match $members) + ~~~~~~~~~~~~~~~~~~~~~~~ + CategoryInfo : OperationStopped: (:) [], ArgumentException + FullyQualifiedErrorId : System.ArgumentException

I found a workaround by adding #$members= $members.Replace("\","\\") fixes the problem but I am not sure if is the best option.

Is my workaroud acceptable or is there a better way of escaping $members parameter?

briantist · Accepted Answer · 2014-08-07 15:41:06Z

[RegEx]::Escape($members)

That will ensure that characters in strings get interpreted as literals and not as part of the RegEx.

To explain further, the -match operator is doing a regular expression match, so the string you pass to it is interpreted as a regular expression.

Backslash happens to be the escape character in a regular expression, so that's where your issue is. Using [RegEx]::Escape() ensures that other characters won't be interpreted, such as [,],.,+,(,),^,$,?,*, etc.

I tested it and it works perfectly. It is better than my workaround because it escapes all special characters and I don't need to recode that logic myself. TA!

Collectives™ on Stack Overflow

How to escape characters inside of a parameter in Powershell?

1 Answer 1

1 Comment

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Related