Hello,

I am new to linux. I am using Fedora Core 6. I have configured xine and mplayer for playing my video files. Some of my video files have extension .dat Those files are on a DVD, so I cant rename those files. Double clicking on it doesn't open in default application (xine), instead it gives a security error. All other extensions like avi and mpg plays well except .dat. However I am able to play .dat files by right clicking on it and using open with. Can anyone help me why double clicking doesn't work!!

The exact error message as shown in the dialog window is below,
------------------------------------------------------------------------------
Cannot open rojapontho.DAT
The filename "rojapontho.DAT" indicates that this file is of type "dat document". The contents of the file indicate that the file is of type "AVI video". If you open this file, the file might present a security risk to your system.

Do not open the file unless you created the file yourself, or received the file from a trusted source. To open the file, rename the file to the correct extension for "AVI video", then open the file normally. Alternatively, use the Open With menu to choose a specific application for the file.
------------------------------------------------------------------------------

I hope by doing some minor change in some settings this can be solved. Kindly help me.

If you right-click on the file, a menu will pop up. If the application you want isn't in the list, select "Open With"->"Open with Other Application". Enter the player you want (e.g., /usr/bin/mplayer). It will now appear in the "Open With" menu.

In my query itself I mentioned I am able to play dat files by right clicking and using openwith. I just want to know, is it possible to disable "that security feature", which prevents opening files, when the extension does not match with the content. Thanks for your interest in helping me.

I'm not seeing the problem on FC6. I placed an avi in a .dat file, and Nautilus correctly identifies it as an avi, offering to open it with a media player. Are you current in your maintenance?

I dont understand what maintenance I need to do. But in my system also it identifies the content. But it does not allow to open on double clicking. This may be due to some SELinux setting (I doubt). But I tried something, and I couldn't find out what exactly I need to do.

SELinux is not involved in this. As to maintenance:

yum -y update

Have you tried right-clicking on one of those files, selecting Properties and setting mplayer or vlc as the default player for that type of file? Once you have done so, double-clicking should work fine.

I have set mplayer as default player. But still it doesn't open automatically. it says it is not safe to open and it offers only cancel button. However the dialogbox says I can do it by right clicking and open with. I tried that one and it works (As I mentioned earlier). What I dont understand is that if other machines can open avi video in a .dat file, why not my machine? What is the problem with my machine?

You never answered the question about maintenance; are you running current software?

Sorry for the delayed reply.

I tried to update. But it was taking very long time. So I canceled the process. I would like to tell you that I am using only dial up internet connection with speed about 40 kbps. So is there any way to do off line update? I mean downloading the update file in some other computer, taking it through pen drive and updating my computer. (Like Windows auto patcher)

If I didn't update, what can go wrong? Still I think, I should be able to open files based on the content irrespective of its extension.

Please tell me if I can update only few components which are responsible for this problem. Because I cant think about full update again as it may take time even in days.

Please don't mind my delay in reply. Please help me.

Canceling an update is not a good idea. It can leave your machine in an unstable state. All modern OS depend on network connections (or at least the availability of a machine with a fast connection to download maintenance).

Yes, you can do this. It's a very commonly asked question. Search for: fedora create a local yum repository

However, you will need a big pen drive. Fedora 6 has many gigabytes of updates at this point. Applying maintenance doesn't download that much, as only the needed updates are applied.

You expect software to be fixed without installing the fixes? Do you believe in magic too?

The problem is that software has dependencies (requisites), so frequently, asking for only one package will require many other packages so that they inter-operate correctly.

No problem.

I took my computer to my friends home for broadband access and I tried updating. I manged to download all the rpm files(it took 18 hours for download), but while updating I got an error message saying "Error: hplip conflicts with selinux-policy < 2.4.6-52" and the update process terminated. I have all the rpms in /var/cache/yum/updates/packages. I hope I can use these rpms again instead downloading. Please help me to resolve the conflict.

I reinstalled the package selinux (by removing it and installing a fresh copy). After this I could successfully update using 'yum update'. I again checked whether the update is complete by 'Main menu/System Tools/Software Updater'. It said there is no packages available for your computer. So my system is completely updated.

But the problem still persists. I am unable to open .dat files by double clicking. What else can I do? Please help me.

Yes, I agree with you. But, I think it is true when the update process start installing the packages. When I canceled the update last time, it was not even finished checking the availability of packages. So canceling at that stage should not have done any harm to my computer, I suppose. If I am wrong please correct me.

OK, the only two things I can think of at this point are that either an association has been set incorrectly as a result of a bug before the software update, or that the mime database was not updated correctly as a result of a bug in the maintenance before the update.

You can try to fix the first problem by:

Then logoff and log back in. This will remove any associations you've set in Nautilus, setting them back to default.

If it's still a problem, then as root:

Then logoff and log back in. This will recreate the system file association list.