Write [alt]-[enter] key combination to file

how would I create a string with the <alt>-<enter> key combiniation in the middle of it which I can then write out to a file? Would it be as simple as outputing the unicode characters for <alt> and then <enter>?

It doesn't make sense to write a key combination to a file. It only makes sense to write characters (or bytes) to a file. Could you tell us why you want to do this?

alt and enter are not characters,

enter or return quite often maps to "\n",

http://www.leepoint.net/notes-java/io/10file/sys-indep-newline.html
(re:content in the link, Mac OS X is Unix)