Add comments, add check for required arguments

usr/sbin/sshutterd

@@ -1,18 +1,27 @@
 #!/bin/bash
 
-if [ -f "/etc/sshutter.conf" ]; then
-	. /etc/sshutter.conf
-fi
-
 function log {
 	echo "$(date +'%Y-%m-%d %H:%M:%S') $@"
 }
 
+# Include config file if present
+if [ -f "/etc/sshutter.conf" ]; then
+	. /etc/sshutter.conf
+fi
+
+# Check if args are given
+if [ "$WHITELIST" -eq "" ] || [ "$PORT" -eq "" ] || [ "$TARGET" -eq "" ]; then
+	echo "Error: you need to specify WHITELIST, PORT and TARGET, either in /etc/sshutter.conf or through environment variables." 1>&2
+	exit 1
+fi
+
+# Check if permissions are high enough
 if [ "$UID" -ne 0 ]; then
 	echo "Error: must be root." 1>&2
 	exit 1
 fi
 
+# Main loop
 while [ true ]; do
 	ping -c 3 "$TARGET" 1>/dev/null
 	if [ "$?" -eq 0 ]; then