Review feedback.

Author: Marcelo Vanzin

bin/spark-shell

@@ -41,7 +41,7 @@ usage() {
 export -f usage
 
 if [[ "$@" = *--help ]] || [[ "$@" = *-h ]]; then
-  usage 0
+  usage "" 0
 fi
 
 # SPARK-4161: scala does not assume use of the java classpath,

launcher/src/main/java/org/apache/spark/launcher/Main.java

@@ -44,8 +44,8 @@ class Main {
    * "bin/spark-class2.cmd" batch script on Windows to execute the final command.
    * <p/>
    * On Unix-like systems, the output is a list of command arguments, separated by the NULL
-   * character. On Windows, the output is single command line suitable for direct execution
-   * form the script.
+   * character. On Windows, the output is a command line suitable for direct execution from the
+   * script.
    */
   public static void main(String[] argsArray) throws Exception {
     checkArgument(argsArray.length > 0, "Not enough arguments: missing class name.");
@@ -139,7 +139,7 @@ private static List<String> prepareBashCommand(List<String> cmd, Map<String, Str
   }
 
   /**
-   * Internal launcher used when command line parsing fails. This will behave differently depending
+   * Internal builder used when command line parsing fails. This will behave differently depending
    * on the platform:
    *
    * - On Unix-like systems, it will print a call to the "usage" function with two arguments: the

launcher/src/main/java/org/apache/spark/launcher/SparkSubmitCommandBuilder.java

@@ -29,13 +29,13 @@
 import static org.apache.spark.launcher.CommandBuilderUtils.*;
 
 /**
- * Special launcher for handling a CLI invocation of SparkSubmit.
+ * Special command builder for handling a CLI invocation of SparkSubmit.
  * <p/>
- * This launcher extends SparkLauncher to add command line parsing compatible with
- * SparkSubmit. It handles setting driver-side options and special parsing needed
- * for the different specialClasses.
+ * This builder adds command line parsing compatible with SparkSubmit. It handles setting
+ * driver-side options and special parsing behavior needed for the special-casing certain internal
+ * Spark applications.
  * <p/>
- * This class has also some special features to aid PySparkLauncher.
+ * This class has also some special features to aid launching pyspark.
  */
 class SparkSubmitCommandBuilder extends AbstractCommandBuilder {