2010/4/1 Murali K. Vemuri <[email protected]>: > On Wed, 2010-03-31 at 16:24 +0200, Denys Vlasenko wrote: > >> Why is this needed/useful? > > I have a board where I cannot add telnet and all I have is console. > if fflush_all() were in its original position, my console refreshes > every often and that is a problem as I might be doing something else on > that console. this fflush_all() draws blank. > > currently if we mention "-t" , screen is flushed and new header is > displayed. when we don't mention "-t", only blank screen is refreshed, > time and again. > > So, when we mention "-t", watch does not dump anything on the terminal > but every now and then re-flushes.
Yes, because you are using the wrong tool: you use watch as if it is cron or runsv! Stop doing that. -t only controls whether header will or will not be printed, but command's output is always printed. I think your program prints nothing, but watch still should display that "nothing", because that's what watch is supposed to show - the output of the new command's invocation. > re-flushing a screen on which this > application does not actually dump anything ... does not sound good. Yes, it does sound good. watch _expects_ that the program will give some output. Empty string is an output too. >> > The user specifies the -t option only if he wants to do the "watch" >> > silently. if the screen refreshes every often, does not look nice. >> >> Why do you think -t means "watch silently"? >> > If "-t" was not supposed to be the "silently" option, why does it not > dump a header? Because -t means "do not print the header", and nothing else! It does not mean "do not clear the screen if program printed nothing", as you seem to think. "watch -n5 -t true" should clear screen every 5 seconds and then print output of "true" - empty string. -- vda _______________________________________________ busybox mailing list [email protected] http://lists.busybox.net/mailman/listinfo/busybox
