deal with more than one connected device/emulator

xwords4/android/scripts/adb_uninstall.sh

@@ -1,3 +1,27 @@
 #!/bin/sh
 
-adb uninstall org.eehouse.android.xw4
+set -e -u
+
+INDEX=0
+
+usage() {
+    echo "usage: $0 [--help] [-n <index>]"
+    echo "uninstall crosswords from the <index>th device"
+    exit 0
+}
+
+while [ $# -ge 1 ]; do
+    case $1 in
+        -n)
+            shift
+            INDEX=$1
+            ;;
+        *) usage
+            ;;
+    esac
+    shift
+done
+
+SERIAL="$(adb devices | grep 'device$' | sed -n  "$((1+INDEX)) p" | awk '{print $1}')"
+
+adb -s $SERIAL uninstall org.eehouse.android.xw4