Perhaps it should be said that personal use of gpg and the use that a system administrator makes of it and key-ing are different use-cases. So we might expect fewer assumptions to hold and greater mystery :-)
On Sat, Jun 26, 2021, 1:53 PM <to...@tuxteam.de> wrote: > On Sat, Jun 26, 2021 at 08:42:26AM -0400, Cindy Sue Causey wrote: > > On 6/26/21, Andrei POPESCU <andreimpope...@gmail.com> wrote: > > [...] > > > > Well, it makes perfect sense if you remember that "everything is a > > > file", even if there are exceptions (e.g. network devices). > > > > > > Hopefully I'm reading this right. While on dialup, I spent A LOT of > > time battling a well-known closed source modem tty* driver. Out of > > desperation, I could sometimes get it to work by copying it between > > hard drives that contained separate operating systems. > > > > BUT you can't just e.g. "cp" or "right click > copy" it over. It would > > fail with a "Can't copy special file" error message. I know this > > because I just did it again with ttyS0. You CAN rsync it between > > partitions, and it would be viable, usable. > > Wait a sec. You are not trying to copy /dev/ttyS0 (or its kin)? > > Because that won't really make much sense. Or, well, it will perhaps > do surprising things. > > See, /dev/ttyS0 is a representation of an external device (your first > serial interface, if your computer still has such a thing). You can > open it, read from it (which will yield incoming characters), write > to it (which will send the characters out, if all goes well) -- so > to your applications it presents an interface similar to the one > a file presents. This is Andrei's quote "everything is a file". > > If you now copy /dev/ttyS0 to /tmp, e.g. > > sudo cp /dev/ttyS0 /tmp > > and assuming there's something connected to it and sending us characters, > there will be an ever-growing /tmp/ttyS0 and the copy will terminate > the moment the serial connection's other side "hangs up". > > Now if you do > > sudo cp -a /dev/ttyS0 /tmp > > you get something completely different: a device file (referring to the > exact same device as your original). > > Don't forget to remove them after: your system administrator might get > mighty confused finding a device file in /tmp :-) > > Cheers > - t >
