diff --git a/xwords4/android/scripts/install_all.sh b/xwords4/android/scripts/install_all.sh
index 095146817..dcd2626e4 100755
--- a/xwords4/android/scripts/install_all.sh
+++ b/xwords4/android/scripts/install_all.sh
@@ -15,10 +15,10 @@ DEVICES="$(adb devices | grep 'device$' | awk '{print $1}')"
 while [ $# -ge 1 ]; do
     case $1 in
         -e)
-            DEVICES="$DEVICES $(adb devices | grep '^emulator' | awk '{print $1}')"
+            DEVICES="$(adb devices | grep '^emulator' | awk '{print $1}')"
             ;;
         -d)
-            DEVICES="$DEVICES $(adb devices | grep -v emulator | grep 'device$' | awk '{print $1}')"
+            DEVICES="$(adb devices | grep -v emulator | grep 'device$' | awk '{print $1}')"
             ;;
         -p)
             [ $# -gt 1 ] || usage "-p requires an argument"