diff --git a/lib/util/devutil.js b/lib/util/devutil.js
index 33bcba3b..96859616 100644
--- a/lib/util/devutil.js
+++ b/lib/util/devutil.js
@@ -50,17 +50,17 @@ devutil.listPidsByComm = function(adb, serial, comm, bin) {
         .then(function(properties) {
           var version = properties['ro.build.version.release']
           if (version.match(/^8\./) !== null) {
-            commands["ps"] = 'ps -lef'
+            commands.ps = 'ps -lef'
           }
           else {
-            commands["ps"] = 'ps'
+            commands.ps = 'ps'
           }
           resolve(commands)
         })
     }
   })
   .then(function(commands) {
-     return adb.shell(serial, [commands["ps"]])
+     return adb.shell(serial, [commands.ps])
             .then(function(out) {
               return new Promise(function(resolve) {
                 var header = true