\s is used in win32forth to end interpretation of a file. Other forth systems may use different names;
\\ is common as well. Here is a definition that will work in ANS Forth Systems, if there is no such word.
: \s begin refill 0= until ;
Found in comp.lang.forth ; Aleksej Saushev; Dec 13, 9:19 pm. Works with gforth; mka 14.12.2008.