Powershell: Find/Replace pattern of ASCII control characters

This expression:

@("[char]3 [char]0 [char]2 [char]3 [char]1")

...creates an array with a single element. You need commas between terms if you really want an array of 5 items, but -replace does not support arrays anyway. Also, your single element contains the literal characters you typed; not what you expected.

What you need is to create a simple string to feed to -replace; this is a bit more involved when you are dealing with non-printable characters. You had the right idea--you just have to tell PowerShell to interpolate the code expressions within your string using the $() notation on each expression:

$CR = "$([char]3)$([char]0)$([char]2)$([char]3)$([char]1)"

Michael Sorens' helpful answer explains the problem with your approach well and offers a working solution.

To offer a simpler alternative:

$CR = ([char[]] (3, 0, 2, 3, 1)) -join ''

• 3, 0, 2, 3, 1 creates an array of integers with the Unicode code points of the characters to create.

• Cast [char[]] converts the code points to actual characters ([char]).

• -join '' joins the array of characters (with no separator) to for a single string.

I have a function in a script that does something like this. Not sure if this will help you:

# This function will make a new file that has custom comments# it will comment out "rollback tran"# it will uncomment out "--commit tran"function CommentAndUncomment($TheScript){    PrintTextAndTime("About to run this SQL file: $TheScript")    PrintTextAndTime("Will comment out 'rollback tran' and uncomment '--commit tran'")    $content = Get-Content $TheScript    $content |       ForEach-Object {         if ($_ -clike "*ROLLBACK TRAN;*") {           $_ -replace "ROLLBACK TRAN;", "--ROLLBACK TRAN;"        }         elseif ($_ -clike "*--COMMIT TRAN;*") {           $_ -replace "--COMMIT TRAN;", "COMMIT TRAN;"        }        else{            $_        }      } |       Set-Content $ModifiedCommentsFile    echo $ModifiedCommentsFile    sqlcmd -i $ModifiedCommentsFile    del $ModifiedCommentsFile}