[CentOS] Re: Reboots -- everything's a file

From: Rodrigo Barbosa <rodrigob at suespammers.org>
> Actually, there is another neat trick for rpm based systems.
> You see, rpm, prior to removing anything, will rename that to ${NAME}.OLD.
> So, libc.so.6 becomes libc.so.6.OLD, and then removed.
> As we all know, if that library is currently open by any running process,
> it won't be imediately removed (even tho you can't see it with a 'ls').
> The trick is pretty simple: lsof | grep OLD
> That, of course, only aplies if you are doing everything using RPM
> (yum, redhat-update, apt-get).

That's because open file handles work in inode number, not filename.
So you can rename things out-of-the-way for existing file handles,
while creating a new file that will be opened for any new ones.

Devices, processes, etc... in UNIX pretty much have the same logic
as files.  Which is why I love UNIX -- everything acts like a file,
with similar meta-data, etc...


--
Bryan J. Smith   mailto:b.j.smith at ieee.org