How can I lock screen on lxde
You should be able to bind the screensaver lock command to CTRL+ALT+L by editing your Lubuntu keyboard & mouse configuration file
Add the following to ~/.config/openbox/lubuntu-rc.xml
<keybind key="C-A-L">
<action name="Execute">
<command>xscreensaver-command -lock</command>
</action>
</keybind>
This should be located inbetween the XML tags
<keyboard>
...
</keyboard
Logout and login for the changes to take effect.
I would elaborate/combine some of the answers. First (in a terminal) start your editor:
vi ~/.config/openbox/lubuntu-rc.xml
Then search for the mentioned faulty code:
<keybind key="C-A-L">
<action name="Execute">
<command>xscreensaver-command -lock</command>
</action>
</keybind>
and change it to use the dm-tool:
<keybind key="C-A-L">
<action name="Execute">
<command>dm-tool lock</command>
</action>
</keybind>
Then add a section, so the Windows+L combination works too:
<keybind key="W-L">
<action name="Execute">
<command>dm-tool lock</command>
</action>
</keybind>
Finally, finish the editor (saving the file) and activate it:
openbox --reconfigure
Good luck and thanks for all the answers found here...
We can also use "lxlock" command that's provided by the lxde.
I just found it on Ubuntu 14.04.
We can add the below lines in our openbox config file in the keyboard. vim $HOME/.config/openbox/lubuntu-rc.xml
<!-- keybinding for Screen Lock-->
<keybind key="W-L">
<action name="Execute">
<command>lxlock</command>
</action>
And then restart the openbox with the following command.
openbox --restart
This will enable locking of the desktop by hitting Windows Key + L