[monitor] Fix shellcheck warnings, typo

Change-Id: Iccedb32e03eb2b446497d040cc5533ced5a4979a
diff --git a/monitor/install.sh b/monitor/install.sh
index 64fe278..7f503a5 100755
--- a/monitor/install.sh
+++ b/monitor/install.sh
@@ -13,8 +13,8 @@
 # 4. Follow the instructions
 
 # Full path
-BASE=`readlink -fn -- "$0"`
-BASE=`dirname "$BASE"`
+BASE=$(readlink -fn -- "$0")
+BASE=$(dirname "$BASE")
 if [ ! -x "$BASE/bot-status" ]; then
   echo "Make sure the install script is in the monitor directory"
   exit 1
@@ -33,7 +33,7 @@
 MANY=0
 for json in "$BASE"/*.json; do
   if [ "$JSON" = "" ]; then
-    JSON="`basename $json`"
+    JSON="$(basename "$json")"
   else
     MANY=1
   fi
@@ -99,5 +99,5 @@
 
 # Crontab
 echo " * To run the application every five minutes, add this line to your crontab:"
-echo "   */5 * * * * $ROOT/bin/bot-status $ROOT/bin/$JSON $ROOT/html/index/html"
+echo "   */5 * * * * $ROOT/bin/bot-status $ROOT/bin/$JSON $ROOT/html/index.html"
 echo