I frequently have to ssh to a remote system that, if faced with N minutes of inactivity (where N is rather small), will terminate my connection. I'm getting tired of being kicked off and losing my work/context just because, e.g., I went to look something up on the web and it took a little long.
I've been trying to come up with a simple script that I can run in the background that merely sends a small amount of output to the terminal now and then, so I will not be logged off.
Of course, ideally, I'd like the output not to interfere with whatever I'm doing, regardless of what I'm doing -- plain text, curses, whatever.
So I'm looking for some tput capability(s) that will reset the I/O timer, but result in a noop regarding screen appearance. I've found a lot of things that come close, but so far, all of them could conceivably result in a glitch if the timing is wrong.
What I'm currently doing is
echo -e "$(tput sc)$(tput rc)\c"
(save cursor, restore cursor). This has served me well so far, but I'm sure it's just a matter of time before it happens between some curses program doing it's own save/restore and getting messed up.
cub and/or cuf (cursor back, cursor forward) look like they could almost work. If either of them moved the cursor not-at-all when given a 0 parameter, that would be exactly what I'm looking for. But, unfortunately for me, 0 behaves exactly like 1 (cursor moves one position in whatever direction). At least, for the terminal I'm using, it does.
echo -e "$(tput cub1)$(tput cuf1)"
works great, except if it happens when the cursor is at the left edge of the screen. The cub1, in that case, does nothing, but then the cuf1 moves the cursor.
If I reversed them:
echo -e "$(tput cuf1)$(tput cub1)"
then I'd only have trouble if it happened while the cursor was sitting at the right edge of the screen, and I suppose that probably happens less often. Still...
If I could figure out how to get the cursor's current position, I'd get it, and then use it to cup to where it already is. But there doesn't seem to be a way to get the cursor's current position. (Or did I just miss it?)
mrcup with 0's for parameters might work if my terminal supported mrcup, but it doesn't.
Things like
echo -e '\c'
and
cat /dev/null
result in nothing at all going to the terminal, and so don't reset the inactivity timer.
Seems like there should be some simple way.
Any ideas?
I think I have it: