Cfrgtkky

How can I lock my desktop screen from the command line?

You can lock the computer by running gnome-screensaver-command with the -l flag like so:

gnome-screensaver-command -l

However this will only work if you have Gnome Screensaver running for your session (should be - unless you've disabled it) you can start that from the commandline with:

gnome-screensaver

gnome-screensaver-command -l

If you're in a different (desktop) session (e.g. virtual console, switched to another login, SSH), specify the display explicitly (:0 is the default display):

DISPLAY=:0 gnome-screensaver-command -l

To unlock, use the -d (--deactivate) option.

gnome-screensaver-command --lock will do it.

Under KDE dm-tool lock will work (for me on Kubuntu 15.04).

In newer versions of GNOME 3, gnome-screensaver is no more.

The generic solution seems to be

xdg-screensaver lock

You also can call dbus directly instead (source):

dbus-send --type=method_call --dest=org.gnome.ScreenSaver /org/gnome/ScreenSaver org.gnome.ScreenSaver.Lock

It also seems they have taken away the possibility to unlock the screen from the command line.

Here is a long way of accomplishing it (adding a quicker way below):

to make it even easier to lock, you can add an executable script to an executable path, call it "lock" and then the locking of your screen will be as easy as typing "lock" in cli

Here's how to do it:

mkdir ~/bin

vim ~/bin/lock

#!/bin/bash

gnome-screensaver-command -l

save and quit

chmod +x ~/bin/lock

don't forget to add ~/bin to your ~/.profile - note the dot at the beginning of the file name
one word of caution about this, make sure you add it to the right file. Here is what the .profile says about it:

# This file is not read by bash(1), if ~/.bash_profile or ~/.bash_login

# exists.

therefore you want to first check if the above-mentioned files exist in your home directory, you should add it there, if they don't exist, then add the path to bin to the .profile

vim ~/.profile # or one of the the other files if they exist

append the following at the end:

# set PATH so it includes user's private bin directories

PATH="$HOME/bin:$HOME/.local/bin:$PATH"

at this point you can launch the following shortcut from cli

you@yourUbuntu:~$ lock

[EDIT] Here is the quick and easy way to do it:
add an alias to your ~/.bashrc file, which is executed every time a shell is opened, thus ensuring Alias persists:

vim ~/.bashrc

# set lockscreen

alias lock="gnome-screensaver-command -l"

the result is the same, but quicker