General :: Splitting Text Files Into Parts With 2000 Lines

I am facing a problem while splitting a text file, I need to split a file into some parts and each split file should have 2000 lines, when I do it through "split" command the mother file is kept intact but as per my requirement I need to cut mother file into some parts thus it should not be kept intact.

Example:
file size
motherfile.txt 5000 lines.
after split
motherfile.txt 2000 lines.
childfile1.txt 2000 lines.
childfile2.txt 1000 lines.