I recently updated my linux distribution(fedora core3) to fedora core4 and for the first time opte'd for KDE as display manager. Everything went smoothly until I used the console. The problem is that the shell doesnt recognise commands like shutdown and init. to be able to use them I have to issue those commands with their absolute path, i.e /sbin/init 6 for eg. worst, there are some commands that are not "recognised" by the shell. for example clock, hwclock --show. when entered the command which clock to see whether it is found in the PATH variable, a get a negative response. Can someone tell me what is the problem.. are there bugs in the distribution(I got the installation disk with a linux magazine).. Or is part of KDE behaviour

Very unlikely that that is caused by KDE. As normal user, your path-variable mostly contains directories in /usr and no ref to /sbin and other sbin-directories. So that is why the shell can't find the commands. This is (to my knowledge) quite normal. Maybe you changed the path-variable once while you were using FC3 and forgot about it (or the default setup for FC3 differs from FC4).

PS checked on a RH8 box (only references to directories in /usr and to /home/username/bin) and on Slack (a few directories as well but no sbin-directories).