> These two last points, if you really decide to implement them like that in
> the final version, may require some synchronization, e.g. via file locking.
> It is not impossible (I mean, it is quite unlikely, but especially with
> automated CI systems not impossible *at all*) for two SSH sessions to
> come in practically at once, and I have indeed seen shell startup scripts
> run the same program at the same time.
Good point. If I understood everything correctly, this can be easily 
solved by the "flock" command, right?

> It would be... interesting to have one login session write the first line,
> then another session immediately write the second one, and then neither of
> them will find exactly one line in the file 🙂 And same for logout.
Indeed.


Have a nice weekend!

Paul