Index: Gruntfile.js
===================================================================
--- Gruntfile.js	(revision 26042)
+++ Gruntfile.js	(working copy)
@@ -123,6 +123,26 @@
 				options: {
 					curly: false,
 					eqeqeq: false
+				},
+				// Process only one file passed from cli
+				// Run with grunt jslint:core --target=filename.js
+				filter: function( filepath ) {
+					var target = grunt.option('target');
+
+					// Don't filter when no target file specified
+					if ( ! target ) {
+						return true;
+					}
+
+					// Normalize filepath for Win
+					filepath = filepath.replace(/\\/g, '/');
+
+					// Match only the filename passed from cli
+					if ( filepath.lastIndexOf( '/' + target ) == filepath.length - ( target.length + 1 ) ) {
+						return true;
+					}
+
+					return false;
 				}
 			}
 		},