Hacky-Hacky notify-send hack for sending from cron(tab).

notify-send-remote.sh

#!/bin/bash
# Hacky-Hacky notify-send hack for sending from cron(tab).
# Copyright (C) 2016 Christoph criztovyl Schulz
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
notify-send-remote()
{
    #Args: user summary message
    user=$1
    summary=$2
    message=$3
    mfile="messageto"$user$RANDOM

    # The .dbus_session_bus_address file is should contain the current dbus session bus address in following form:
    #  "export DBUS_SESSION_BUS_ADDRESS=[session bus address]"
    # Best way to achieve this is to add the following script to your startup applications:
    #  echo "export DBUS_SESSION_BUS_ADDRESS=$DBUS_SESSION_BUS_ADDRESS" > ~/.dbus_session_bus_address
    # You may use the z-dbus-session-export files  in this gist. (copy the .desktop file to ~/.config/autostart and the .sh file to ~/.local/opt/dbus_session_export.sh)
    cd /home/$user &&
        echo ". .dbus_session_bus_address && notify-send \"$summary\" \"$message\"" > $mfile &&
        chown $user:$user $mfile && chmod +x $mfile &&
        sudo -u $user "/bin/bash" "./$mfile" &&
        rm $mfile
}
notify-send-remote "$1" "$2" "$3"

z-dbus-session-export-autostart.desktop

[Desktop Entry]
Comment=
Terminal=false
Name=DBUS Session Export
Exec=/opt/dbus-session-export.sh
Type=Application

z-dbus-session-export.sh

#!/bin/bash
umask 277
file="$HOME/.dbus_session_bus_address"
[ -f $file ] && rm -f $file
[ $DBUS_SESSION_BUS_ADDRESS ] && echo "export DBUS_SESSION_BUS_ADDRESS=$DBUS_SESSION_BUS_ADDRESS" > $file || echo "No dbus session"

z-install.sh

#!/bin/bash
case $1 in
    "install")
        ln -s z-dbus-session-export-autostart.desktop /etc/xdg/autostart/
        mkdir -p /opt/
        ln -s z-dbus-session-export.sh /opt/dbus-session-export.sh
        chmod a+x /opt/dbus-session-export.sh
        ;;
    "uninstall"|"remove")
        rm -f /etc/xdg/autostart/z-dbus-session-export.sh
        rm -f /opt/dbus-session-export.sh
        ;;
    *|"help")
        echo "Usage: $0 install|remove"
        ;;
esac