Please try "man csh", and see pushd's comment.

 >         pushd n
 >                 With no arguments, pushd exchanges the top two elements of
 >                 the directory stack.  Given a name argument, pushd changes
 >                 to the new directory (ala cd) and pushes the old current
 >                 working directory (as in csw) onto the directory stack.
					    ^^^

 What is "csw"?

 cwd?
 csh?

----------------------------------------------------------
		SAITOH Masanobu (msaitoh@spa.is.uec.ac.jp)
		University of Electro-Communications