Hi all,
Here is my problem.
I run KDE as my Desktop Env. Now no flame wars please, I just happen to prefer it, but I have just noticed a very strange thing and hope someone can answer it for me.
When using Konqueror to browse my files, and more specifically, my config files in my /ETC directory, I have some files which when I hover my mouse over them, shows in the popup window to be PLAIN TEXT files. while others show up as DIFF files, even though they are both files with the extension .conf.
If I rename the file that shows as a DIFF file by changing it´s extension to be, for example, .txt, then the mouseover shows it to be a PLAIN TEXT file, but if I then rename it back again, it reverts to a DIFF file.
I even have some files that though they have an extension of .conf, show up as C++ files.
Now this is not really a great problem, but purely to fill my curiosity, and to allow me to learn even more about Linux, does anyone have any idea why this happens, and how to tell what file type is what, NOT based on it´s extension.

TIA

open a console and type:

file --help

it is a program to determine the type of files.

My guess is that KDE uses a combination of file extension and use of the 'file' utility mentioned by __J (or something similar) in order to determine file type. If renaming the file extension had an effect on KDE's assessment of what kind of file it is, then clearly it's making some suppositions based on that. The 'file' utility tries to identify files by contents, rather than extension. It's very often accurate. However, I can see where guessing based on extension would be useful, too; you may have a text file (with a .txt extension, to remind yourself what kind of file it is) that contains part of a diff. You want the file to be treated as plain text, rather than viewed in a diff-viewer of some kind. Plain text files can include many different types of data; 'file' tries to distinguish different types.

But actually, I have no idea what method KDE uses to determine file type.

OK,
Have done as suggested, and the command:- file -modules.conf returns this----modules.conf: ASCII text.
But, in KDE konqueror, it shows as a Diff file. Is this then a bug in Konqueror/KDE, or is there some more obvious reason that I don´t know about?

Have done a little more digging, and it seems that KDE determines file type from the Mime type, so I can only conclude that something in KDE is broken. Any idea where to find the right configuration file for KDE mime types registration?

More info,
I have looked at these files using XFM, and they show as plain text files as I would expect. Also using XFCE, TWM, FLUXBOX etc they show as plain text files, which would siggest that this is a problem with KDE and/or Konqueror.
Anyone else any suggestions