Linux Desktop How to shutdown, restart or logoff gnome via command / Launcher

It is true that Gnome desktop provides nice facility to logoff, shutdown or restart computer with dialog. You can create a nice shortcut to avoid the GUI confirmation dialog box to speed up work.

(A) Shutdown computer
i) Right click on Desktop > Select Create Launcher
ii) Type the Command in text box “sudo /sbin/shutdown -h 0” and for rest of properties refer following figure:

iii) Click Close to save. Please note that only root will be able to shutdown system. However with the help of sudo it is possible that non-privileged can also shutdown the system (without password). Type following commands:
a) Login as root user

b) Type visudo command:
#visudo

c) Append following text of line, so that all commands will be excuted without password.
vivek localhost= NOPASSWD: /sbin/shutdown -h 0
vivek localhost= NOPASSWD: /sbin/reboot

By default, sudo requires that a user authenticate him or herself before running a
command. This behavior is modified with NOPASSWD flag i.e. shutdown and reboot command would allow user vivek run as root on the localhost as root without authenticating (password) himself

d)Save the file and replace command in above figure with sudo /sbin/shutdown -h now and close the dialog Launcher dialog box.

(B) Restart computer
i) Right click on Desktop > Select Create Launcher
ii) Type the Command in text box “sudo /sbin/restart” and for rest of properties refer following figure:

(C) Logoff Gnome

i) Right click on Desktop > Select Create Launcher
ii) Type the Command in text box “/usr/bin/gnome-session-save --kill” and for rest of properties refer following figure:

iii) Make sure you turnoff user logout dialog box. Type command OR Click on Applications > Desktop Preferences > Advanced > Sessions and clear the option box 'Prompt on logout' > Click close to save changes.

You can also use logoff script, to logoff KDE/Gnome desktop session. All these hacks should also work with FreeBSD or OpenSolaris desktop.