Function to count number of lines in a text file

Question

Need a function that will accept a filename as parameter and then return the number of lines in that file.

Should be take under 30 seconds to get the count of a 10 m

Answer 1

Too large files...
The following is the fastest-effeciently way I know of:

Dim oFso, oReg, sData, lCount
Const ForReading = 1, sPath = "C:\file.txt"
Set oReg = New RegExp
Set oFso = CreateObject("Scripting.FileSystemObject")
sData = oFso.OpenTextFile(sPath, ForReading).ReadAll
With oReg
    .Global = True
    .Pattern = "\r\n" 'vbCrLf
    '.Pattern = "\n" ' vbLf, Unix style line-endings
    lCount = .Execute(sData).Count + 1
End With
WScript.Echo lCount
Set oFso = Nothing
Set oReg = Nothing