HDDS-730. ozone fs cli prints hadoop fs in usage

Closes #1464

hadoop-ozone/common/src/main/bin/ozone

@@ -178,7 +178,7 @@ function ozonecmd_case
       OZONE_RUN_ARTIFACT_NAME="hadoop-ozone-recon"
     ;;
     fs)
-      HADOOP_CLASSNAME=org.apache.hadoop.fs.FsShell
+      HADOOP_CLASSNAME=org.apache.hadoop.fs.ozone.OzoneFsShell
       OZONE_RUN_ARTIFACT_NAME="hadoop-ozone-tools"
     ;;
     scmcli)

hadoop-ozone/ozonefs/src/main/java/org/apache/hadoop/fs/ozone/OzoneFsShell.java

@@ -0,0 +1,100 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.fs.ozone;
+
+import java.io.IOException;
+import java.io.PrintStream;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.LinkedList;
+import org.apache.hadoop.classification.InterfaceAudience;
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.conf.Configured;
+import org.apache.hadoop.fs.FsShell;
+import org.apache.hadoop.fs.shell.Command;
+import org.apache.hadoop.fs.shell.CommandFactory;
+import org.apache.hadoop.fs.shell.FsCommand;
+import org.apache.hadoop.security.UserGroupInformation;
+import org.apache.hadoop.tools.TableListing;
+import org.apache.hadoop.tracing.TraceUtils;
+import org.apache.hadoop.util.StringUtils;
+import org.apache.hadoop.util.Tool;
+import org.apache.hadoop.util.ToolRunner;
+import org.apache.htrace.core.TraceScope;
+import org.apache.htrace.core.Tracer;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/** Provide command line access to a Ozone FileSystem. */
+@InterfaceAudience.Private
+public class OzoneFsShell extends FsShell {
+
+  private final String ozoneUsagePrefix = "Usage: ozone fs [generic options]";
+
+  /**
+   * Default ctor with no configuration.  Be sure to invoke
+   * {@link #setConf(Configuration)} with a valid configuration prior
+   * to running commands.
+   */
+  public OzoneFsShell() { this(null); }
+
+  /**
+   * Construct a OzoneFsShell with the given configuration.  Commands can be
+   * executed via {@link #run(String[])}
+   * @param conf the hadoop configuration
+   */
+  public OzoneFsShell(Configuration conf) { super(conf); }
+
+  protected void registerCommands(CommandFactory factory) {
+    // TODO: DFSAdmin subclasses FsShell so need to protect the command
+    // registration.  This class should morph into a base class for
+    // commands, and then this method can be abstract
+    if (this.getClass().equals(OzoneFsShell.class)) {
+      factory.registerCommands(FsCommand.class);
+    }
+  }
+
+  @Override
+  protected String getUsagePrefix() {
+    return ozoneUsagePrefix;
+  }
+
+  /**
+   * main() has some simple utility methods
+   * @param argv the command and its arguments
+   * @throws Exception upon error
+   */
+  public static void main(String argv[]) throws Exception {
+    OzoneFsShell shell = newShellInstance();
+    Configuration conf = new Configuration();
+    conf.setQuietMode(false);
+    shell.setConf(conf);
+    int res;
+    try {
+      res = ToolRunner.run(shell, argv);
+    } finally {
+      shell.close();
+    }
+    System.exit(res);
+  }
+
+  // TODO: this should be abstract in a base class
+  protected static OzoneFsShell newShellInstance() {
+    return new OzoneFsShell();
+  }
+}