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kded4 - KDE daemon - triggers Sycoca database updates when needed.

KDED4(8) KDE User's Manual KDED4(8)


kded4 - KDE daemon - triggers Sycoca database updates when needed.


kded4 [--help] [Generic options] [Qt-options] [KDE-options] [--check]


kded4 is responsible for creating the sycoca file, i.e. the binary cache of servicetypes, mimetypes, and services for a particular user.
It monitors the directories containing .desktop files. When a file is added/removed, it waits 5 seconds (in case of a series of updates), and then launches kbuildsycoca4 to update the sycoca.
It checks newly installed update files, i.e. the *.upd files used to update configuration files of users when the configuration file formats changes. kconf_update is launched to do the updates.
When the hostname changes, it will make the necessary changes to the KDE environment and X-server to allow continued proper operation, launching kdontchangethehostname to do the changes.
Those tasks are also performed always at kded4 start to ensure that the user configuration is up to date.
It is also responsible for launching the on-demand kded4 modules and init enabled kded4 modules like:
Konqueror Browser Preloader
Reduces Konqueror startup time.
Directory Watcher
Monitors directories for changes.
Hardware Detection
Provides a user interface for hardware events.
SSL Certificate Policy
Provides the user configured SSL certificate policy to applications.
Network Proxy Configuration
Automatic proxy configuration.
Password Caching
Temporary password caching, for example: so that a webpage with HTTP authentication doesn't ask for your password for every link and every image in the page. These passwords are forgotten when exiting KDE (unlike KWallet)
Sound Policy
Provides the sound system policy to applications.
Stores website icons.
Display Management
Manages displays and video outputs.
Cookie jar
Stores network cookies.
Network Watcher
Keeps track of the network and updates directory listings of the network:/ KIO slave.
Subversion Module
Provides various subversion actions to filemanager and other software.
Network Status
Tracks status of network interfaces and provides notifications for applications using the network.
Write Daemon
Watches the messages from local users sent with write(1) or wall(1).
Notification area watcher
Keeps track of applications that want to use the D-Bus based notification area.
KMixD Mixer Service
Systemtray daemon
Keeps track of applications that want to use the D-Bus based system tray.
Keyboard Daemon
Keeps track of keyboard changes (new keyboard, changed layout)
Remote URL Change Notifier
Provides change notifications for network folders
Activity Manager
The Nepomuk activities manager backend
Display Management change monitor
Notifies how the display has been rotated (where available)
Free Space Notifier
Warns when running out of space in your home folder.
Removable Device Automounter
Automatically mounts devices as needed.
Nepomuk Search Module
Helper module for KIO to ensure automatic updates of Nepomuk search listings.
Power Management
Battery, Display and CPU power management and notifications.
K Remote Control Daemon
Manages the Remote Control commands received
Status Notifier Manager
Manages services that provide status notifier user interfaces.
DNS-SD Service Discovery Monitor
Monitors the network for DNS-SD services.
Drive Ejector
Automatically unmounts and releases drives when their eject button is pushed.
Time zone
Provides access to the system's time zones for applications.
Input Actions
Input Actions service performing configured actions on key presses.
The init modules can be enabled/disabled using systemsettings, in System Administration > Startup and Shutdown > Service Manager.


Show author information.
Show help about options.
Show all options.
Show KDE specific options.
Show Qt specific options.
Show license information.
-v --version
Show version information


Check Sycoca database only once.


If kded4 is called without parameters and is already running, it shows the message:
KDE Daemon (kded) already running.
If kded4 is called with kded4 --check, then it updates the KDE sycoca using kbuildsycoca4.


kdeoptions(7), qtoptions(7), kbuildsycoca4(8)


There are probably tons of bugs. Use[1] to report them.


David Faure <>
Waldo Bastian <>


2010-10-28 KDE 4.5