HADOOP-3714. Add a new contrib, bash-tab-completion, which enables bash tab completion for the bin/hadoop script. Contributed by Chris Smith.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/core/trunk@676653 13f79535-47bb-0310-9956-ffa450edef68

CHANGES.txt

@@ -48,6 +48,10 @@ Trunk (unreleased changes)
     HADOOP-3149. Adds a way in which map/reducetasks can create multiple 
     outputs. (Alejandro Abdelnur via ddas)
 
+    HADOOP-3714.  Add a new contrib, bash-tab-completion, which enables 
+    bash tab completion for the bin/hadoop script. See the README file
+    in the contrib directory for the installation. (Chris Smith via enis)
+
   IMPROVEMENTS
 
     HADOOP-3577. Tools to inject blocks into name node and simulated

src/contrib/bash-tab-completion/README

@@ -0,0 +1,11 @@
+Bash tab completion support for the hadoop script.
+
+On Debian-like distributions, the script can be placed in
+/etc/bash_completion.d/, and it will be sourced automatically by Bash. On
+other distributions, you may source the file manually (`. hadoop.sh') or
+source it from your bashrc (or equivalent) file.
+
+The script allows tab completion of all the command names, subcommands for the
+'fs', 'dfsadmin', 'job', 'namenode' and 'pipe' commands, arguments of the 'jar'
+command and most arguments to the 'fs' subcommands (completing local and 
+dfs paths as appropriate).

src/contrib/bash-tab-completion/hadoop.sh

@@ -0,0 +1,121 @@
+#!/usr/bin/env bash
+
+# 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.
+
+# Provides tab completion for the main hadoop script.
+#
+# On debian-based systems, place in /etc/bash_completion.d/ and either restart
+# Bash or source the script manually (. /etc/bash_completion.d/hadoop.sh).
+
+_hadoop() {
+  local script cur prev temp
+
+  COMPREPLY=()
+  cur=${COMP_WORDS[COMP_CWORD]}
+  prev=${COMP_WORDS[COMP_CWORD-1]}  
+  script=${COMP_WORDS[0]}  
+  
+  # Bash lets you tab complete things even if the script doesn't
+  # exist (or isn't executable). Check to make sure it is, as we
+  # need to execute it to get options/info
+  if [ -f "$script" -a -x "$script" ]; then
+    case $COMP_CWORD in
+    1)
+      # Completing the first argument (the command).
+
+      temp=`$script | grep -n "^\s*or"`;
+      temp=`$script | head -n $((${temp%%:*} - 1)) | awk '/^ / {print $1}' | sort | uniq`;
+      COMPREPLY=(`compgen -W "${temp}" -- ${cur}`);
+      return 0;;
+
+    2)
+      # Completing the second arg (first arg to the command)
+
+      # The output of commands isn't hugely consistent, so certain
+      # names are hardcoded and parsed differently. Some aren't
+      # handled at all (mostly ones without args).
+      case ${COMP_WORDS[1]} in
+      dfs | dfsadmin | fs | job | pipes)
+        # One option per line, enclosed in square brackets
+
+        temp=`$script ${COMP_WORDS[1]} 2>&1 | awk '/^[ \t]*\[/ {gsub("[[\\]]", ""); print $1}'`;
+        COMPREPLY=(`compgen -W "${temp}" -- ${cur}`);
+        return 0;;
+
+      jar)
+        # Any (jar) file
+
+        COMPREPLY=(`compgen -A file -- ${cur}`);
+        return 0;;
+
+      namenode)
+        # All options specified in one line,
+        # enclosed in [] and separated with |
+        temp=`$script ${COMP_WORDS[1]} -help 2>&1 | grep Usage: | cut -d '[' -f 2- | awk '{gsub("] \\| \\[|]", " "); print $0}'`;
+        COMPREPLY=(`compgen -W "${temp}" -- ${cur}`);
+        return 0;;
+
+      *)
+        # Other commands - no idea
+
+        return 1;;
+      esac;;
+
+    *)
+      # Additional args
+      
+      case ${COMP_WORDS[1]} in
+      dfs | fs)
+        # DFS/FS subcommand completion
+        # Pull the list of options, grep for the one the user is trying to use,
+        # and then select the description of the relevant argument
+        temp=$((${COMP_CWORD} - 1));
+        temp=`$script ${COMP_WORDS[1]} 2>&1 | grep -- "${COMP_WORDS[2]} " | awk '{gsub("[[ \\]]", ""); print $0}' | cut -d '<' -f ${temp}`;
+
+        if [ ${#temp} -lt 1 ]; then
+          # No match
+          return 1;
+        fi;
+
+        temp=${temp:0:$((${#temp} - 1))};
+
+        # Now do completion based on the argument
+        case $temp in
+        path | src | dst)
+          # DFS path completion
+          temp=`$script ${COMP_WORDS[1]} -ls "${cur}*" 2>&1 | grep -vE '^Found ' | cut -f 1 | awk '{gsub("^.* ", ""); print $0;}'`
+          COMPREPLY=(`compgen -W "${temp}" -- ${cur}`);
+          return 0;;
+
+        localsrc | localdst)
+          # Local path completion
+          COMPREPLY=(`compgen -A file -- ${cur}`);
+          return 0;;
+
+        *)
+          # Other arguments - no idea
+          return 1;;
+        esac;;
+
+      *)
+        # Other subcommands - no idea
+        return 1;;
+      esac;
+    esac;
+  fi;
+}
+
+complete -F _hadoop hadoop