return EWTF;

I’m in the mood for sharing my tips and tricks. TechBase has some nice bash functions for the user you built KDE as (kde-devel for most people). However, if you installed as another user, there are two common tasks: running a KDE 4 app from your normal user’s account, and switching to your kde-devel user and running a KDE 4 app from there.

A few functions in your main user’s .bashrc and in kde-devel’s .bashrc make all this simple.

Disclaimer: these functions are tailored to my set up (Arch Linux) and will probably need adapting for your system. Especially the kde3 and qt3 functions.

First of all: running KDE 4 apps as your normal user. Put the following in your user’s ~/.bashrc (you just insert removefrom, qt4-copy and kde4 if you like):

function removefrom()
{
    local varname=$1
    local entry="$2"

    unset newvar
    for value in `IFS=: eval echo \\$$varname`; do
	if [ "$value" != "$entry" ]; then
	    newvar="${newvar}${newvar+:}${value}"
	fi
    done

    # Set it again
    eval $varname="$newvar"
    unset newvar
}

function qt3()
{
    removefrom PATH $QTDIR/bin
    removefrom LD_LIBRARY_PATH $QTDIR/lib
    removefrom PKG_CONFIG_PATH $QTDIR/lib
    removefrom MANPATH $QTDIR/man

    source /etc/profile.d/qt.sh

    echo "Using QT 3 ($QTDIR)"
}

function qt4()
{
    removefrom PATH $QTDIR/bin
    removefrom LD_LIBRARY_PATH $QTDIR/lib
    removefrom PKG_CONFIG_PATH $QTDIR/lib
    removefrom MANPATH $QTDIR/man

    source /etc/profile.d/qt4.sh

    echo "Using system QT 4 ($QTDIR)"
}

function qt4-copy()
{
    removefrom PATH $QTDIR/bin
    removefrom LD_LIBRARY_PATH $QTDIR/lib
    removefrom PKG_CONFIG_PATH $QTDIR/lib
    removefrom MANPATH $QTDIR/man

    export QTDIR=/home/kde-devel/build/qt-copy
    export PATH=$QTDIR/bin:$PATH
    export LD_LIBRARY_PATH=$QTDIR/lib:$LD_LIBRARY_PATH
    export PKG_CONFIG_PATH=$QTDIR/lib:$PKG_CONFIG_PATH
    export MANPATH=$MANPATH:$QTDIR/man
    export QMAKESPEC=$QTDIR/mkspecs/linux-g++

    echo "Using QT 4 from KDE SVN ($QTDIR)"
}

function kde3()
{
    qt3

    # Remove the current KDE from variables
    removefrom PATH $KDEDIR/bin
    removefrom LD_LIBRARY_PATH $KDEDIR/lib
    unset QT_PLUGIN_PATH
    unset KDEHOME
    unset KDETMP
    unset KDEVARTMP

    # Add the new ones
    source /etc/profile.d/kde.sh

    echo "Using KDE 3 ($KDEDIR)"
}

function kde4()
{
    qt4-copy

    # Remove the current KDE from variables
    removefrom PATH $KDEDIR/bin
    removefrom LD_LIBRARY_PATH $KDEDIR/lib
    removefrom PKG_CONFIG_PATH $KDEDIR/lib/pkgconfig

    # Add the new one
    export KDEDIR=/home/kde-devel/kde
    export KDEDIRS=$KDEDIR
    export KDEHOME=$HOME/.kde4
    export KDETMP=${TMPDIR-/tmp}/kde4-$USER
    export KDEVARTMP=/var/tmp/kde4cache-$USER
    export KDE_DATA_DIRS=$KDEDIR/share
    export PATH=$KDEDIR/bin:$PATH
    export XDG_CONFIG_DIRS=$KDEDIR/etc/xdg
    export QT_PLUGIN_PATH=$KDEDIR/lib/plugins
    export LD_LIBRARY_PATH=$KDEDIR/lib:$LD_LIBRARY_PATH
    export PKG_CONFIG_PATH=$KDEDIR/lib/pkgconfig:$LD_LIBRARY_PATH
    export KDE_COLOR_DEBUG=1

    # Ensure that they exist
    mkdir -p $KDEDIR $KDETMP $KDEVARTMP

    echo "Using KDE 4 ($KDEDIR)"
}

Now you can type “kde4” at a prompt, and thereafter you are in a KDE4 environment. So typing konqueror will give you Konqi from KDE 4 (exactly how I’m typing this post). “kde3” will get you back to a KDE 3 session.

Now for switching to kde-devel. The problem is that you want kde-devel to have the magic cookie that allows it to connect to your X server. Your normal user needs to give it out like so:

function go-kde()
{
    xauth list $DISPLAY | sed "s/^.*$DISPLAY/$DISPLAY/" > /tmp/x.auth
    sudo su - kde-devel
    rm -f /tmp/x.auth
}

Typing “go-kde” should now take you to a kde-devel session, with your magic cookie saved in /tmp/x.auth. But how do applications find out about it? Put the following in kde-devel’s ~/.bashrc:

if [ -f /tmp/x.auth ]; then
	xauth add $(cat /tmp/x.auth)
fi

Easy, huh?

So: you’ve installed KDE 4 under the kde-devel user (following the instructions at TechBase). Now you want to try out KDE 4 in all its glory, but as your main user. Well, here’s how.

First of all, we’ll need a script that sets up the environment and starts KDE 4. /home/kde-devel/kde/bin/startkde does most of this, of course, but it expects some things set up first, like PATH. To this end, we’ll set up a couple of bash functions that give us a KDE environment. Create a file /home/kde-devel/bin/startkde4 with the following contents:

#!/bin/bash

# startkde4

function removefrom()
{
    local varname=$1
    local entry="$2"

    unset newvar
    for value in `IFS=: eval echo \\$$varname`; do
	if [ "$value" != "$entry" ]; then
	    newvar="${newvar}${newvar+:}${value}"
	fi
    done

    # Set it again
    eval $varname="$newvar"
    unset newvar
}

if [ -n "$QTDIR" ]; then
    removefrom PATH $QTDIR/bin
    removefrom LD_LIBRARY_PATH $QTDIR/lib
    removefrom PKG_CONFIG_PATH $QTDIR/lib
    removefrom MANPATH $QTDIR/man
fi

export QTDIR=/home/kde-devel/build/qt-copy
export PATH=$QTDIR/bin:$PATH
export LD_LIBRARY_PATH=$QTDIR/lib:$LD_LIBRARY_PATH
export PKG_CONFIG_PATH=$QTDIR/lib:$PKG_CONFIG_PATH
export MANPATH=$MANPATH:$QTDIR/man
export QMAKESPEC=$QTDIR/mkspecs/linux-g++

# Remove the current KDE from variables
if [ -n "$KDEDIR" ]; then
    removefrom PATH $KDEDIR/bin
    removefrom LD_LIBRARY_PATH $KDEDIR/lib
    removefrom PKG_CONFIG_PATH $KDEDIR/lib/pkgconfig
fi

# Add the new one
export KDEDIR=/home/kde-devel/kde
export KDEDIRS=$KDEDIR
export KDEHOME=$HOME/.kde4
export KDETMP=${TMPDIR-/tmp}/kde4-$USER
export KDEVARTMP=/var/tmp/kde4cache-$USER
export KDE_DATA_DIRS=$KDEDIR/share
export PATH=$KDEDIR/bin:$PATH
export XDG_CONFIG_DIRS=$KDEDIR/etc/xdg
export QT_PLUGIN_PATH=$KDEDIR/lib/plugins
export LD_LIBRARY_PATH=$KDEDIR/lib:$LD_LIBRARY_PATH
export PKG_CONFIG_PATH=$KDEDIR/lib/pkgconfig:$LD_LIBRARY_PATH
export KDE_COLOR_DEBUG=1

# Ensure that they exist
mkdir -p $KDEDIR $KDETMP $KDEVARTMP

exec /home/kde-devel/kde/bin/startkde

Of course, you can turn most of this file into a bash function called kde4 and place it into your ~/.bashrc, then turn your terminal into a place to run kde4 apps from (in your kde3/gnome/whatever session) by typing “kde4” at the prompt.

Now make sure it’s executable (chmod +x /home/kde-devel/bin/startkde4).

Finally, we need a session for KDE4. In /etc/X11, there should be a folder called sessions. This should contain kde.desktop. You can copy this to kde4.desktop and edit it to look like the following (ie: change the Name, Exec and TryExec):

[Desktop Entry]
Encoding=UTF-8
Type=XSession
Exec=/home/kde-devel/bin/startkde4
TryExec=/home/kde-devel/bin/startkde4
Name=KDE4
Comment=The K Desktop Environment. A powerful Open Source graphical desktop environment

Now you should be able to select “KDE4” as the session type in KDM and log in to a KDE 4 session.