The kfontinst command-line tool does not allow a font to be reinstalled from the command line.  This functionality is important because many fonts are under active development, with new versions being released on occasion.  (Also because there exist bugs with the font management application in systemsettings, such as Bug 361960, that prevents fonts from being installed or removed that way.)

Steps to reproduce:
1. Install a font (say, foo.ttf) using any method desired.
2. Attempt to install a font with the same filename using kfontinst:
$ kdesu kfontinst foo.ttf

Observed results:
3. The following error dialog appears:

> Installing — Font Installer
> 
> Error
> 
> /usr/local/share/fonts/f/foo.ttf already exists.
> 
> [ Cancel ]

Expected results:
3. A warning dialog should appear that informs me that the font already exists and asks me whether I want to replace it.  (It would also be helpful if the warning dialog could be bypassed by using a command-line parameter such as --force.)