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== Introduction ==
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{{Moved To Userbase}}
KDE defines a filesystem hierarchy which is used by the KDE environment
 
itself as well as all KDE applications. In general KDE stores all its
 
files in a fixed directory tree.
 
 
 
By default there are two such directory trees, one at the system
 
level and one at the user level in the user's home directory. However,
 
as a system administrator you can create additional trees.
 
 
 
KDE and KDE applications look up files by scanning the directory trees.
 
The directory trees are in order of precedence. When a file is
 
present in multiple directory trees, the file from the first listed
 
tree takes precendence.
 
Normally, the tree located in the user's home directory has the highest
 
precedence. This is also the directory tree where changes are
 
written to.
 
 
 
For configuration files the story is slightly
 
different. If there are multiple configuration files found in the directory
 
trees with the same name their content is combined. The precedence order
 
of the directory trees plays a role here. When two files define the same
 
configuration key, the file with the highest precedence determines which
 
value is used for the key.
 
 
 
== Location of the Directory Trees ==
 
 
 
The location of the KDE Directory Trees is determined by a number of
 
environment variables, each of which is covered below.
 
 
 
=== $KDEHOME ===
 
This environment variable determines the location of the user level
 
directory tree and is used by KDE applications for creating and saving
 
files. This directory tree has the highest precedence; files or settings
 
found in this directory tree will take precendent over any files or settings
 
found in other directory trees.
 
 
 
This directory tree is, as the name already suggests, normally located in the home directory of the user. If this environment variable is not defined the default location $HOME/.kde is used.
 
 
 
If the environment variable has a value that starts with a tilde (~), the tilde is replaced with the users home directory at runtime. In order to use this care must be taken to add proper quoting, otherwise the shell might do the expansion already resulting in undesired behaviour in combination with su.
 
 
 
=== $KDEROOTHOME ===
 
In order to prevent problems where applications that run as root save
 
files with root-privileges in the user's home directory, the $KDEROOTHOME
 
environment variable has been introduced in the KDE 3.x series. Applications
 
that run with uid 0 (root) will use this variable to determine the location of
 
the user level directory and where to save their files. If this variable is
 
not defined the home directoy of the root user is looked up in the password
 
file and .kde is appended. Usually that results in /root/.kde .
 
 
 
=== $KDEDIRS ===
 
It is possible to specify multiple system level directory trees. This makes it possible to let groups of users use a directory tree dedicated for their group. Such an additional directory tree can contain additional applications, specialized application resources or a specific set of default configurations suitable for the group. Specifying default configurations this way instead of using a /etc/skel construction has as advantage that changes in the default configuration can be made after the account of the user has been created.
 
 
 
The directories in $KDEDIRS should be seperated with a colon (:). The directories are listed in precedence order, the first directory has highest precedence, the last one lowest precedence.
 
 
 
Since a group level directory tree should normally override any settings present at the system level, one would list the group level directory tree before the system level directory tree.
 
 
 
In general communication, references to the directory trees are made in
 
terms of $KDEHOME to indicate the applicable user level directory tree,
 
and in terms of $KDEDIRS to indicate any of the system level directory trees.
 
 
 
==== Example ====
 
 
 
A staff member at a university could have the following settings:
 
 
 
 
 
<code>
 
KDEHOME='~/.kde3'
 
KDEROOTHOME='/root/.kde3'
 
KDEDIRS='/opt/kde_staff:/opt/kde3'
 
</code>
 
 
 
In this example the user settings are saved under the .kde3 directory
 
in the user's home directory. Applications that run as root will save their
 
settings to /root/.kde3 . KDE 3 has been installed to /opt/kde3 but there is
 
also an additional directory tree located at /opt/kde_staff . Configuration
 
files under that directory will take precedent over the ones in the /opt/kde3
 
system directories. /opt/kde-staff could contain additional applications that
 
should only be available to staff members.
 
 
 
 
 
== Directory Tree ==
 
 
 
Each directory tree used by KDE has a fixed directory structure. Directories
 
that are not relevant for a certain tree can be left out though. For example,
 
directories used for temporary files are usually only found under $KDEHOME but
 
not in any other directory tree.
 
 
 
 
 
The KDE runtime environment combines the sub-directories found under the
 
various directory trees and refers to them as a single KDE resource. The
 
KDE resource name is listed in the tables below.
 
 
 
 
 
There are three broad categories: files that are CPU/architecture
 
specific, files that are host specific and files that are not specific with
 
regards to host, CPU or architecture.
 
 
 
CPU/architecture specific directories:
 
 
 
{|
 
|-
 
! Directory !! KDE&nbsp;resource !! Description
 
|-
 
| {{path|bin/}} || exe || Used for KDE executables.
 
|-
 
| {{path|cgi-bin/}} || cgi || CGI scipts that can be used by the KDE Help Center
 
|-
 
| {{path|lib/}} || lib || Used for KDE libraries.
 
|-
 
| {{path|lib/kde3/}} || module || This directory contains components, plugins and other runtime loadable objects for use by KDE 3.x applications.
 
|}
 
 
 
The following are host specific directories. They are only available under
 
$KDEHOME and are normally symlinked to locations outside the $KDEHOME
 
directory tree.
 
 
 
{|
 
! Directory !! KDE&nbsp;resource !! Description
 
|-
 
| {{path|socket-&lt;HOSTNAME&gt;}} || socket || This directory contains communication sockets. The filesystem used by $KDEHOME may not be suitable for communication sockets. For that reason this directory is by default symlinked to another location.
 
|-
 
| {{path|tmp-&lt;HOSTNAME&gt;}} || tmp || This directory is used for temporary files. The filesystem used by $KDEHOME may be on a network. For performance reasons this directory is therefor by default symlinked to another location which is more likely to be on a local filesystem.
 
|-
 
| {{path|cache-&lt;HOSTNAME&gt;}} || cache || New in KDE 3.2. This directory is used for cached information such as HTTP objects, formatted help pages and the system configuration cache (ksycoca).
 
 
 
Since this is non-essential information this directory is by default
 
sylinked to a location outside $KDEHOME to help making backups of other
 
information easier and to make it easier to reclaim diskspace.
 
|}
 
 
 
The majority of directories involves data that is not CPU, architecture or
 
host specific, all these directories are prefixed with {{path|share/}}:
 
 
 
{|
 
! Directory !! KDE&nbsp;resource !! Description
 
|-
 
| {{path|share/applnk/}} || apps || Contains .desktop files describing the KDE-menu.
 
|-
 
| {{path|share/apps/}} || data || Contains applications specific data files. Each application has a sub-directory here for storing its files.
 
|-
 
| {{path|share/config/}} || config || Contains configuration files. Configuration files are normally named after the application they belong to followed by "rc". There are also files that are specific to a component and as such referenced by all applications that use that component. A special case is "kdeglobals", this file is read by all KDE applications.
 
|-
 
| {{path|share/config/session/}} || - || This directory is used by session management and is normally only available under $KDEHOME. At the end of a session KDE applications store their state here. The file names start with the name of the application followed by a number. The session manager "ksmserver" stores references to these numbers when saving a session in "ksmserverrc".
 
|-
 
| {{path|share/doc/HTML/}} || html || Documentation of KDE applications is stored here. Documentation is categorized by language and the application it belongs to.
 
 
 
Normally at least two files can be found in a directory: "index.docbook" which contains the documentation in the unformatted docbook format and "index.cache.bz2" which contains the same documentation formatted as bzip2 compressed html. The html version is used by khelpcenter, if the html version is missing it will regenerate it from the docbook version but this is a time-consuming process.
 
|-
 
| {{path|share/icons/}} || icon || Under this directory icons are stored. Icons are categorized per theme, dimension and usage category.
 
|-
 
| {{path|share/mimelnk/}} || mime || In this directory .desktop files that describe mimetypes are stored.
 
|-
 
| {{path|share/services/}} || services || This directory contains .desktop files that describe services. Services and Applications are very similar, the major difference is that a Service is usually used by other Services or Applications while an Application is in general started by the user. Services do not appear in the KDE menu.
 
|-
 
| {{path|share/servicetypes/}} || servicetypes || This directory contains .desktop files that describe servicetypes. A servicetype usually represents a certain programming interface. Applications and Services include in their .desktop files the servicetypes that they provide.
 
|-
 
| {{path|share/sounds/}} || sound || This directory contains sound files.
 
|-
 
| {{path|share/templates/}} || templates || This dir contains templates for creating files of various types. A template consists of a .desktop file that describes the file and that includes a reference to a file in the .source sub-directory. The templates in this directory appearem in the "Create New" menu available on the desktop and in the file browser. When a user selects a template from the menu its source file is copied.
 
|-
 
| {{path|share/wallpapers/}} || wallpaper || This directory contains images that can be used as background picture.
 
|}
 
 
 
== Outside the Directory Tree ==
 
 
 
As mentioned in the description of the directory tree, there are three host-specific directories that are usually symlinked to other locations. If the directories do not already exist, the following symlinks and directories will be created using the lnusertemp utility. Since both /tmp and /var/tmp are world writable, there is a possibility that one of the mentioned directories already exists but is owned by another user. In that case the lnusertemp utility will create a new directory with an alternative name and link to that instead.
 
 
 
=== Sockets ===
 
Symlink: {{path|$KDEHOME/socket-&lt;HOSTNAME&gt;}}
 
 
 
Default destination: {{path|/tmp/ksocket-&lt;USER&gt;/}}
 
 
 
<tt>lnusertemp&nbsp;socket</tt> creates a directory for local communication sockets and point a symlink to it. The combined length of the directory name and the name of any communication socket should not exceed 106 characters. By default this directory is created under /tmp, other locations can be used by setting the KDETMP environment variable.
 
 
 
=== Temporary Files ===
 
Symlink: {{path|$KDEHOME/tmp-&lt;HOSTNAME&gt;}}
 
 
 
Default destination: {{path|/tmp/kde-&lt;USER&gt;/}}
 
 
 
<tt>lnusertemp&nbsp;tmp</tt> creates a directory for temporary files and points a symlink to it. For performance reasons it is recommended to have this directory on a local filesystem but this is not strictly necassery.
 
 
 
=== Cache Files ===
 
Symlink: {{path|$KDEHOME/cache-&lt;HOSTNAME&gt;}}
 
 
Defualt destination: {{path|/var/tmp/kdecache-&lt;USER&gt;/}}</code>
 
 
 
<tt>lnusertemp&nbsp;cache</tt> creates a directory for cache files and points a symlink to it. For performance reasons it is recommended to have this directory on a local filesystem but this is not strictly necassery.
 
 
 
The system configuration cache (ksycoca and ksycocastamp) is located in here. It is recommended NOT to delete these files during boot since that will slow down the startup of KDE.
 
 
 
By default this directory is created under /var/tmp, other locations
 
can be used by setting the $KDEVARTMP environment variable.
 
 
 
== Adding Lookup Locations ==
 
 
 
KDE applications look up data files using the resource names listed in the
 
[#dir_structure Directory Tree] section.  The KDE runtime
 
environment translates these names to actual directories. It does so
 
by combining the locations of the directory trees with the directories
 
listed in the tables.
 
 
 
==== Defining Search Paths ====
 
 
 
A user has the following directory tree settings:
 
 
 
<code>
 
KDEHOME='~/.kde3'
 
KDEDIRS='/opt/kde_staff:/opt/kde3'
 
</code>
 
 
 
When an application now looks for a "wallpaper" file, to each of the
 
directory trees the directory "share/wallpapers/" is added. All of the
 
resulting directories are then searched for the file:
 
 
 
<code>
 
~/.kde3/share/wallpapers/
 
/opt/kde_staff/share/wallpapers/
 
/opt/kde3/share/wallpapers/
 
</code>
 
 
 
By adding more directory tree to the KDEDIRS environment variable
 
it is possible to expand the number of directories that are being searched.
 
Sometimes it is desirable to include only a single directory in a search
 
but not a whole directory tree. Additional directories can be configured
 
in the kdeglobals configuration file in the "Directories" section.
 
To do so assign one or more directories to the key "dir_" followed by the
 
name of the resource. Multiple directories are seperated by a commas (,).
 
 
 
==== Adding a Resource Directory ====
 
 
 
To add the directory /data/photos to the wallpaper resource, put the
 
following two lines in kdeglobals:
 
 
 
<code>
 
[Directories]
 
dir_wallpaper=/data/photos
 
</code>
 
 
 
When the application now looks for wallpaper files, it will look in the
 
following locations:
 
 
 
<code>
 
/data/photos
 
~/.kde3/share/wallpapers/
 
/opt/kde_staff/share/wallpapers/
 
/opt/kde3/share/wallpapers/</code>
 

Latest revision as of 13:22, 11 March 2016

This page is now on the Userbase wiki.


This page was last edited on 11 March 2016, at 13:22. Content is available under Creative Commons License SA 4.0 unless otherwise noted.