I'm trying to retrace my steps with something. I have Debian Wheezy installed on a pc, a netbook and now the Raspberry Pi, all using the minimal DWM window manager. I use wvdial to connect and had been starting it with 'sudo wvdial' until finding I could alter the permissions of /usr/bin/wvdial to let it run after only entering 'wvdial'. I had thought I'd used 'chmod u+s /usr/bin/wvdial' but that hasn't worked on the Pi. It may be that wvdial is starting but then is blocked from starting ppp due to ppp's permissions. I'm sure I didn't change any other permissions before so was 'chmod u+s...' correct or should it have been 'chown...' or 'chmod a+x...?'

Initially the Pi is setup without the ability to use su and sudo doesn't require a password, so maybe this explains it in some way.

I'm tempted to change the permissions of other files but don't yet know how many this might involve and don't fancy ending up having to reinstall if things get messy, after such a custom setup as I'd pursued.

Thanks for any replies.

Perhaps using inotify or some helper daemons such as inotifyd or incrond will help you to figure out what is accessing what when you're using your system.... That's one of the few ways I know one could track what is going on in the filesystem to the depth which you are asking.

If you're using LVM for your filesystems you can take a snapshot of your root file system before making any changes. That way if you mess up you can revert the snapshot back without too much hassle (much less hassle than a complete reinstall).