Is there enough information to know what this regex is searching and replacing?

Question

Could anyone explain what's being replaced here?

I don't know if enough information is present to understand what's being searched and what's being replaced:

    regEx.Pattern = "(\s) *(\S)"
    regEx.Global = True
    that = regEx.Replace(that, "$1$2")

Answer 1

\s is a whitespace character, such as a tab or a space. \S is any other character. So this preserves the first whitespace character and strips out all following spaces (specifically spaces, not any whitespace character) that occur before a printing character. I'm guessing maybe it's to "clean" lines that use both tab and space indentation, though this seems like a pretty lousy way to do that.