diff --git a/js/ui/runDialog.js b/js/ui/runDialog.js
index 487aeb11b..6f98738cd 100644
--- a/js/ui/runDialog.js
+++ b/js/ui/runDialog.js
@@ -2,6 +2,7 @@
 
 const Big = imports.gi.Big;
 const Clutter = imports.gi.Clutter;
+const Gio = imports.gi.Gio;
 const GLib = imports.gi.GLib;
 const Lang = imports.lang;
 const Mainloop = imports.mainloop;
@@ -24,6 +25,144 @@ const DIALOG_WIDTH = 320;
 const DIALOG_PADDING = 6;
 const ICON_SIZE = 24;
 const ICON_BOX_SIZE = 36;
+const MAX_FILE_DELETED_BEFORE_INVALID = 10;
+
+function CommandCompleter() {
+    this._init();
+}
+
+CommandCompleter.prototype = {
+    _init : function() {
+        this._changedCount = 0;
+        this._paths = GLib.getenv('PATH').split(':');
+        this._valid = false;
+        this._updateInProgress = false;
+        this._childs = new Array(this._paths.length);
+        this._monitors = new Array(this._paths.length);
+        for (let i = 0; i < this._paths.length; i++) {
+            this._childs[i] = [];
+            let file = Gio.file_new_for_path(this._paths[i]);
+            let info = file.query_info(Gio.FILE_ATTRIBUTE_STANDARD_TYPE, Gio.FileQueryInfoFlags.NONE, null);
+
+            if (info.get_attribute_uint32(Gio.FILE_ATTRIBUTE_STANDARD_TYPE) != Gio.FileType.DIRECTORY)
+                continue;
+
+            this._paths[i] = file.get_path();
+            this._monitors[i] = file.monitor_directory(Gio.FileMonitorFlags.NONE, null);
+            if (this._monitors[i] != null) {
+                this._monitors[i].connect("changed", Lang.bind(this, this._onChanged));
+            }
+        }
+        this._update(0);
+    },
+
+    _onGetEnumerateComplete : function(obj, res) {
+        this._enumerator = obj.enumerate_children_finish(res);
+        this._enumerator.next_files_async(100, GLib.PRIORITY_LOW, null, Lang.bind(this, this._onNextFileComplete), null);
+    },
+
+    _onNextFileComplete : function(obj, res) {
+        let files = obj.next_files_finish(res);
+        for (let i = 0; i < files.length; i++) {
+            this._childs[this._i].push(files[i].get_name());
+        }
+        if (files.length) {
+            this._enumerator.next_files_async(100, GLib.PRIORITY_LOW, null, Lang.bind(this, this._onNextFileComplete), null);
+        } else {
+            this._enumerator.close(null);
+            this._enumerator = null;
+            this._update(this._i + 1);
+        }
+    },
+
+    update : function() {
+        if (this._valid)
+            return;
+        this._update(0);
+    },
+
+    _update : function(i) {
+        if (i == 0 && this._updateInProgress)
+            return;
+        this._updateInProgress = true;
+        this._changedCount = 0;
+        this._i = i;
+        if (i >= this._paths.length) {
+            this._valid = true;
+            this._updateInProgress = false;
+            return;
+        }
+        let file = Gio.file_new_for_path(this._paths[i]);
+        this._childs[this._i] = [];
+        file.enumerate_children_async(Gio.FILE_ATTRIBUTE_STANDARD_NAME, Gio.FileQueryInfoFlags.NONE, GLib.PRIORITY_LOW, null, Lang.bind(this, this._onGetEnumerateComplete), null);
+    },
+
+    _onChanged : function(m, f, of, type) {
+        if (!this._valid)
+            return;
+        let path = f.get_parent().get_path();
+        let k = undefined;
+        for (let i = 0; i < this._paths.length; i++) {
+            if (this._paths[i] == path)
+                k = i;
+        }
+        if (k === undefined) {
+            return;
+        }
+        if (type == Gio.FileMonitorEvent.CREATED) {
+            this._childs[k].push(f.get_basename());
+        }
+        if (type == Gio.FileMonitorEvent.DELETED) {
+            this._changedCount++;
+            if (this._changedCount > MAX_FILE_DELETED_BEFORE_INVALID) {
+                this._valid = false;
+            }
+            let name = f.get_basename();
+            this._childs[k] = this._childs[k].filter(function(e) {
+                return e != name;
+            });
+        }
+        if (type == Gio.FileMonitorEvent.UNMOUNTED) {
+            this._childs[k] = [];
+        }
+    },
+
+    getCompletion: function(text) {
+        let common = "";
+        let notInit = true;
+        if (!this._valid) {
+            this._update(0);
+            return common;
+        }
+        function _getCommon(s1, s2) {
+            let k = 0;
+            for (; k < s1.length && k < s2.length; k++) {
+                if (s1[k] != s2[k])
+                    break;
+            }
+            if (k == 0)
+                return "";
+            return s1.substr(0, k);
+        }
+        function _hasPrefix(s1, prefix) {
+            return s1.indexOf(prefix) == 0;
+        }
+        for (let i = 0; i < this._childs.length; i++) {
+            for (let k = 0; k < this._childs[i].length; k++) {
+                if (!_hasPrefix(this._childs[i][k], text))
+                    continue;
+                if (notInit) {
+                    common = this._childs[i][k];
+                    notInit = false;
+                }
+                common = _getCommon(common, this._childs[i][k]);
+            }
+        }
+        if (common.length)
+            return common.substr(text.length);
+        return common;
+    }
+};
 
 function RunDialog() {
     this._init();
@@ -137,16 +276,55 @@ RunDialog.prototype = {
                 this.close();
         }));
 
+        this._pathCompleter = new Gio.FilenameCompleter();
+        this._commandCompleter = new CommandCompleter();
+        this._group.connect('notify::visible', Lang.bind(this._commandCompleter, this._commandCompleter.update));
         this._entry.connect('key-press-event', Lang.bind(this, function(o, e) {
             let symbol = e.get_key_symbol();
             if (symbol == Clutter.Escape) {
                 this.close();
                 return true;
             }
+            if (symbol == Clutter.slash) {
+                // Need preload data before get completion. GFilenameCompleter load content of parent directory.
+                // Parent directory for /usr/include/ is /usr/. So need to add fake name('a').
+                let text = o.get_text().concat('/a');
+                let prefix;
+                if (text.lastIndexOf(' ') == -1)
+                    prefix = text;
+                else
+                    prefix = text.substr(text.lastIndexOf(' ') + 1);
+                this._getCompletion(prefix);
+                return false;
+            }
+            if (symbol == Clutter.Tab) {
+                let text = o.get_text();
+                let prefix;
+                if (text.lastIndexOf(' ') == -1)
+                    prefix = text;
+                else
+                    prefix = text.substr(text.lastIndexOf(' ') + 1);
+                let postfix = this._getCompletion(prefix);
+                if (postfix != null && postfix.length > 0) {
+                    o.insert_text(postfix, -1);
+                    o.set_cursor_position(text.length + postfix.length);
+                    if (postfix[postfix.length - 1] == '/')
+                        this._getCompletion(text + postfix + 'a');
+                }
+                return true;
+            }
             return false;
         }));
     },
 
+    _getCompletion : function(text) {
+        if (text.indexOf('/') != -1) {
+            return this._pathCompleter.get_completion_suffix(text);
+        } else {
+            return this._commandCompleter.getCompletion(text);
+        }
+    },
+
     _run : function(command) {
         this._commandError = false;
         let f;