On Ubuntu 10 running Gnome:
System -> Preferences -> Screensaver. There’s a checkbox to lock after the screensaver activates, and there’s checkbox and a slider to activate the screensaver after a certain amount of time.
On Fedora Core 18 (Gnome)
Using the GUI tools:
Applications > System Tools > System Settings > Brightness & Lock
From the terminal (to set sleep timeout to 10 minutes / 600 seconds, then require login after 15 minutes / 900 seconds):
gsettings set org.gnome.settings-daemon.plugins.power sleep-display-ac 600 gsettings set org.gnome.settings-daemon.plugins.power sleep-display-battery 600 gsettings set org.gnome.desktop.session idle-delay 600 gsettings set org.gnome.desktop.screensaver idle-activation-enabled 'true' gsettings set org.gnome.desktop.screensaver lock-enabled 'true' gsettings set org.gnome.desktop.screensaver lock-delay 900
On Debian 8 (jessie) it’s in “Settings/Privacy”.
(press Alt-F1 and type “settings”).
To run it from somewhere else,
name of the application is “gnome-control-center”.
On Debian (release 7.4 = wheezy):
The problem with lock/timeout/idle/gnome-screensaver is resolved on a standard install, thru the menu “Applications” in the lowest-leftest corner,
Applications > System Tools > Preferences > System Settings > Brightness and Lock
or thru the menu (with your name) in the lowest-rightest corner,
System Settings > Brightness and Lock
Here, I changed “10 minutes” to “1 hour”;
and I changed “Lock ON” to “Lock OFF” (so the screen blanks but doesn’t require another login)
The Debian package that instituted this is
For Centos 7 running MATE GUI, it’s in the menu under
System -> Preferences -> Look and Feel -> Screensaver. You can turn it off from here, as well as locking the screen when computer is idle.
Also, there is
Power Management button in the bottom toolbar of Screensaver preferences windows where you can change additional settings like dimming the screen, turning it off after certain time, etc.
For Fedora 14, it is in the screensaver settings under something like “require password to return from screensaver.” I don’t remember the exact phrasing as I am not booted in fedora at the moment.
EDIT: I am running GNOME with Fedora 14.
On Centos 7 gui
To prevent screen from locking:
Applications (upper left hand corner of desktop) → System Tools → Settings → Privacy → Left click on Screen Lock → Lock screen after blank for, drop down menu
To prevent screen from going black:
Applications → System Tools → Settings → Power → Blank Screen
For Leap 42.x. If you are using Gnome, go to Activities | Show Applications | Settings | Power | Power Saving. Change it to the number of minutes you desire or simply make it Never.