Sometimes I find it handy to perform power actions from the command line or after running a script.
Its pretty simple
# to shutdown
sudo poweroff
# or
sudo shutdown -h now
# to restart
sudo reboot
# or
sudo shutdown -r now
sudo apt-get install pm-utils
# to suspend
sudo pm-suspend
# to hibernate
sudo pm-hibernate
# to suspend/hibernate hybrid
sudo pm-suspend-hybrid
There is also an alternative method to suspend but I find it less reliable
dbus-send --system --print-reply --dest="org.freedesktop.UPower" /org/freedesktop/UPower org.freedesktop.UPower.Suspend
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