KDE

Overview

KDE is a software project currently comprised of a desktop environment known as Plasma, a collection of libraries and frameworks and several applications.

Appearance

Desktop Settings

To reach desktop settings right click on the desktop and select Configure Desktop. If that option isn't available (it is configurable), you can use the keyboard shortcut Alt+D,Alt+S

Layout
Under the Wallpaper tab there is a 'Layout' option. Desktop Settings -> Wallpaper -> Layout
"Folder View" will allow you to place and interact with items on the desktop.
If you do not use desktop icons (or if you need encouragement for better organization) you can use "Desktop".
"Desktop" layout will not allow items on the desktop and results in almost 20 MiB of memory savings in plasmashell.

Lockscreen

Basic settings such as delay and shortcut can be configured at the System Settings location
System Settings -> Security & Privacy -> Screen Locking
Selecting the Configure Appearance button in the top-right corner will present styling options.

Tips and Tricks

File Manager

Dolphin is the default file manager for Plasma.
See its dedicated page here.

KCMs

Settings in Plasma are provided by KDE Configuration Modules (KCM). These are the various modules or sections of System Settings, but it should be noted that some KCMs are hidden from System Settings. All modules can be managed and launched via the utility kcmshell6.

To list available KCMs:

user $ kcmshell6 --list COPY TO CLIPBOARD

To run a particular module (replacing kcm_kded with the desired module):

user $ kcmshell6 kcm_kded COPY TO CLIPBOARD

Single Click vs Double Click

In order to select between single and double click for opening files and folders you can use System Settings.
System Settings -> Workspace -> General Behavior -> "Clicking files or folders"

Power

Disable Hibernate

Hibernation can be disabled and it's menu entries hidden with the drop-in file /etc/polkit-1/rules.d/99-disable-hibernate.rules.

/etc/polkit-1/rules.d/99-disable-hibernate.rules

// Disable hibernate for all users
polkit.addRule(function(action, subject) {
   if ((action.id == "org.freedesktop.login1.hibernate")) {
      return polkit.Result.NO;
   }
});
polkit.addRule(function(action, subject) {
   if ((action.id == "org.freedesktop.login1.hibernate-multiple-sessions")) {
      return polkit.Result.NO;
   }
});

Disable Suspend

Suspend can be disabled and it's menu entries hidden with the drop-in file /etc/polkit-1/rules.d/99-disable-suspend.rules.

/etc/polkit-1/rules.d/99-disable-suspend.rules

// Disable suspend for all users
polkit.addRule(function(action, subject) {
   if ((action.id == "org.freedesktop.login1.suspend")) {
      return polkit.Result.NO;
   }
});
polkit.addRule(function(action, subject) {
   if ((action.id == "org.freedesktop.login1.suspend-multiple-sessions")) {
      return polkit.Result.NO;
   }
});

End Session Commands

Logging out or shutting down via a command can be useful whether for a non-graphical environment or inclusion in scripts. Whenever a plasma session is involved using the following commands should be preferred over more generic options such as systemctl reboot.

Prompt

DBUS provides methods to open a prompt to end a session (logout, reboot, shutdown).

user $ qdbus6 org.kde.LogoutPrompt /LogoutPrompt promptLogout COPY TO CLIPBOARD

user $ qdbus6 org.kde.LogoutPrompt /LogoutPrompt promptReboot COPY TO CLIPBOARD

user $ qdbus6 org.kde.LogoutPrompt /LogoutPrompt promptShutDown COPY TO CLIPBOARD

user $ qdbus6 org.kde.LogoutPrompt /LogoutPrompt promptAll COPY TO CLIPBOARD

Immediate

Similar commands can be used to initiate the process without any prompt.

user $ qdbus6 org.kde.Shutdown /Shutdown savesession COPY TO CLIPBOARD

user $ qdbus6 org.kde.Shutdown /Shutdown logout COPY TO CLIPBOARD

user $ qdbus6 org.kde.Shutdown /Shutdown logoutAndReboot COPY TO CLIPBOARD

user $ qdbus6 org.kde.Shutdown /Shutdown logoutAndShutdown COPY TO CLIPBOARD

See also

KDE.org
Archwiki:KDE
Wikipedia:KDE