Warning when fs.watch is unavailable, rather than throwing errors

lib/coffee-script/command.js

@@ -44,6 +44,9 @@
     if (opts.version) return version();
     if (opts.require) loadRequires();
     if (opts.interactive) return require('./repl');
+    if (opts.watch && !fs.watch) {
+      printWarn("The --watch feature depends on Node v0.6.0+. You are running " + process.version + ".");
+    }
     if (opts.stdio) return compileStdio();
     if (opts.eval) return compileScript(null, sources[0]);
     if (!sources.length) return require('./repl');
@@ -196,6 +199,7 @@
   };
 
   watch = function(source, base) {
+    if (!fs.watch) return;
     return fs.stat(source, function(err, prevStats) {
       var callback, watcher;
       if (err) throw err;

src/command.coffee

@@ -62,6 +62,9 @@ exports.run = ->
   return version()                       if opts.version
   loadRequires()                         if opts.require
   return require './repl'                if opts.interactive
+  if opts.watch and !fs.watch
+    printWarn "The --watch feature depends on Node v0.6.0+. You are running \
+#{process.version}."
   return compileStdio()                  if opts.stdio
   return compileScript null, sources[0]  if opts.eval
   return require './repl'                unless sources.length
@@ -172,6 +175,7 @@ loadRequires = ->
 # time the file is updated. May be used in combination with other options,
 # such as `--lint` or `--print`.
 watch = (source, base) ->
+  return unless fs.watch
   fs.stat source, (err, prevStats)->
     throw err if err
     watcher = fs.watch source, callback = (event) ->