Using the following program

Cesc = 27.chr
print "#{Cesc}[2J"
print "Hello world\n"

Ruby version 1.4.3 (1999-12-08) [i386-cygwin] clears the screen
Ruby version 1.6.6 (2001-12-26) [i586-mswin32] does not.

Why?
Any suggested fix?

Thanks