I am experimenting with kubuntu in a virtual machine (libvert). Kubuntu installs ubuntu with kde desktop. I'm using latest kubuntu from website.

In konsole terminal, the su command gives "authentication failure" and doesn't login to root after password in entered . Using sudo in the same terminal with a following command, works fine after pw is entered. Elsewhere in system, whenever authentication is needed, e.g., software install, password works fine.

I am using konsole in 3 other virtual machines and also in my non-virtual computer and it does not fail to login to root with su command or su -.

Any ideas? Maybe will post this on kubuntu site if no answer from the kde people.

thanks, tom kosvic

su has been replace by sudo years ago in Ubuntu based systems, mainly for security reasons. Don't use su, if you google for it there are plenty of articles explaining the move by the Ubuntu devs, e.g. this one: https://help.ubuntu.com/community/RootSudo

Thank for the info. I had no idea that the su command being negated in kubuntu terminals was planned. Arch, opensuse, opensuse timbleweed all allow su to activate root. I very often use a root terminal for various things. For one thing , zypper, the opensuse commandline package manager, requires root access for adding, deleting, searching packages. I'm a 20 year linux person and never really thought su to root was a potential problem. This is a good reason for experimenting with other linux distros virtually..

thanks again, tom kosvic

This was changed years ago, so you must not have been an Ubuntu/Kubuntu users in recent years...
sudo has the same options and "man sudo" gives you all the necessary information