diff --git a/tmux.sh b/tmux.sh
index ce30375..0f759b0 100755
--- a/tmux.sh
+++ b/tmux.sh
@@ -1,21 +1,50 @@
 #!/bin/bash
-server="$1"
-shift
+# constants
+code_clear=$'\x05\x15'
+code_send=$'\r'
 
-if ! [[ -e ./vars ]] ; then
-	echo 'Please create a "vars" file using "vars.example" as a template'
+die () {
+	echo "$@"
 	exit 1
-fi
-source ./vars
+}
+
+# directories
+mcserver_root="${XDG_DATA_HOME:-${HOME}/.local/share}/mcserver"
+instances_dir="$mcserver_root/instances"
+
+mkdir -p "$instances_dir"
 
 cmd="$1"
 shift
 
-code_clear=$'\x05\x15'
-code_send=$'\r'
+instance="$1"
+shift
+
+instance_dir="$instances_dir/$instance"
+
+
+# input checks
+if [[ -z "${cmd:+x}" ]] ; then
+	die "Please specify one of start, stop, or command."
+fi
+
+if [[ -z "${instance:+x}" ]] ; then
+	die "Please specify an instance."
+fi
+
+if ! [[ -d "$instance_dir" ]] ; then
+	die "Instance \`$instance\` does not exist. Please create it first."
+fi
+
+cd "$instance_dir"
+
+if ! [[ -e ./vars ]] ; then
+	die 'Please create a "vars" file using "vars.example" as a template.'
+fi
+source ./vars
 
 case "$cmd" in
 	stop) tmux send-keys -t "$TMUX_SESSION" -l "$code_clear" 'stop' "$code_send" ;;
 	command) tmux send-keys -t "$TMUX_SESSION" -l "$code_clear" "$*" "$code_send" ;;
-	*) tmux new-window -t $TMUX_SESSION: "./start.sh" || tmux new-session -s $TMUX_SESSION "./start.sh";;
+	start|*) tmux new-window -t $TMUX_SESSION: "./start.sh" || tmux new-session -s $TMUX_SESSION "./start.sh";;
 esac