Hey all, If you've used watch(1) you know that running a command repeatedly is useful. What I wished for yesterday though, is for a mechanism that notified me when a command succeeded, but is long running -- say an ssh session.
I wondered if I could do it in shell, but figured it might be too tricky to do concisely, so I wrote a C program that combines SIGALRM and SIGCHLD into something that works fairly well (though, I've only tested it on OS X so far, yeah, I know), but probably murders POSIX standards (I haven't written Unix C in a while, so my Stevens books are rusty) Anyway, source is on github: https://github.com/apgwoz/when Example usage: when "make" "xmessage 'that long running build actually worked'" (This is no different than a simple while ! `make` ... of course) But, using -t is where the "magic" happens. Lets say you're waiting for a host to come up on AWS or something: when -t "ssh user@host" "xmessage 'Connected'" When the ssh command finally succeeds, xmessage will pop up saying 'Connected' and the prompt will still be there. Maybe one of you will stop laughing long enough to find it useful. Cheers! Andrew -- http://apgwoz.com
