If you do not want your Ubuntu system from sleeping.

Command

Run as root

cd /etc/polkit-1/localauthority/50-local.d/
touch com.ubuntu.disable-suspend.pkla
nano com.ubuntu.disable-suspend.pkla

##insert the following
[Disable suspend (upower)]
Identity=unix-user:*
Action=org.freedesktop.upower.suspend
ResultActive=no
ResultInactive=no
ResultAny=no

[Disable suspend (logind)]
Identity=unix-user:*
Action=org.freedesktop.login1.suspend
ResultActive=yes
ResultInactive=no
ResultAny=yes

[Disable suspend when others are logged in (logind)]
Identity=unix-user:*
Action=org.freedesktop.login1.suspend-multiple-sessions
ResultActive=yes
ResultInactive=no
ResultAny=yes

##save and reboot system

Solution found from this thread: https://askubuntu.com/questions/452908/how-to-disable-suspend-in-14-04

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