uncaughtException handler should output to stderr, trace should be op…

…t-in with --trace.

lib/jake.js

@@ -40,9 +40,20 @@ var JAKE_VERSION = '0.1.12'
   , tasks;
 
 process.addListener('uncaughtException', function (err) {
-  console.log('jake aborted.');
-  if (err.stack) {
-    console.log(err.stack);
+  var msg;
+  console.error('jake aborted.');
+  if (opts.trace && err.stack) {
+    console.error(err.stack);
+  }
+  else {
+    if (err.stack) {
+      msg = err.stack.split('\n').slice(0, 2).join('\n');
+      console.error(msg);
+      console.error('(See full trace by running task with --trace)');
+    }
+    else {
+      console.error(err.message);
+    }
   }
   process.exit(jake.errorCode || 1);
 });
@@ -78,6 +89,7 @@ usage = ''
     + '  -f, --jakefile FILE        Use FILE as the Jakefile\n'
     + '  -C, --directory DIRECTORY  Change to DIRECTORY before running tasks.\n'
     + '  -T, --tasks                Display the tasks, with descriptions, then exit.\n'
+    + '  -t, --trace                Enable full backtrace.\n'
     + '  -h, --help                 Outputs help information\n'
     + '  -V, --version              Outputs Jake version\n'
     + '';
@@ -706,6 +718,9 @@ optsReg = [
 , { full: 'tasks'
   , abbr: 'T'
   }
+, { full: 'trace'
+  , abbr: 't'
+  }
 , { full: 'help'
   , abbr: 'h'
   }