From http://askubuntu.com/questions/457016/how-to-change-gsettings-via-remote-shell. Set the DBUS_SESSION_BUS_ADDRESS environment variable. The following script helps to get the correct value of that variable. It requires name of the process, that is running on the desktop, on which we want to change the dbus settings. (There can be more than 1 …

discover_session_bus_address.sh

#!/bin/bash 

# Remember to run this script using the command "source ./filename.sh"

# Search these processes for the session variable 
# (they are run as the current user and have the DBUS session variable set)
compatiblePrograms=( nautilus kdeinit kded4 pulseaudio trackerd )

# Attempt to get a program pid
for index in ${compatiblePrograms[@]}; do
    PID=$(pidof -s ${index})
    if [[ "${PID}" != "" ]]; then
        break
    fi
done
if [[ "${PID}" == "" ]]; then
    echo "Could not detect active login session"
    return 1
fi

QUERY_ENVIRON="$(tr '\0' '\n' < /proc/${PID}/environ | grep "DBUS_SESSION_BUS_ADDRESS" | cut -d "=" -f 2-)"
if [[ "${QUERY_ENVIRON}" != "" ]]; then
    export DBUS_SESSION_BUS_ADDRESS="${QUERY_ENVIRON}"
    echo "Connected to session:"
    echo "DBUS_SESSION_BUS_ADDRESS=${DBUS_SESSION_BUS_ADDRESS}"
else
    echo "Could not find dbus session ID in user environment."
    return 1
fi

return 0