first approach

swm.sh

@@ -0,0 +1,37 @@
+#!/usr/bin/env bash
+#
+# Enable all connected montiors, disable all disconnected ones.
+# Multiple monitors will be added to the right of previous ones.
+#
+# Author Thomas Ruoff <Thomas.Ruoff@gmail.com>
+
+set -e
+
+CONNECTED=$( xrandr | grep " connected" | awk '{print $1}')
+DISCONNECTED=$( xrandr | grep "disconnected" | awk '{print $1}')
+
+POSTCMD="herbstclient reload"
+
+
+# turn off all disconnected monitors
+XRANDR_OFF_OPTIONS=""
+for mon in $DISCONNECTED; do
+    XRANDR_OFF_OPTIONS+=" --output $mon --off"
+done
+
+# turn on all connected monitors
+XRANDR_ON_OPTIONS=""
+LAST=""
+for mon in $CONNECTED; do
+    XRANDR_ON_OPTIONS+=" --output $mon --auto"
+    if [ ! -z $LAST ]; then
+        XRANDR_ON_OPTIONS+=" --right-of $LAST"
+    fi
+    LAST=$mon
+done
+
+xrandr $XRANDR_ON_OPTIONS $XRANDR_OFF_OPTIONS &&\
+    echo Activated monitors: ${CONNECTED} &&\
+    $POSTCMD
+
+exit $?