WHEN(1)
NAME
 when - repeatedly runs a command, then another when the first succeeds
SYNOPSIS
 when [-n <seconds>] [-t|-z] [-h] [-v] <conditional> <command>
DESCRIPTION
 when runs conditional every N seconds awaiting for "success." Success
 is defined in one of two ways. In timebomb mode, -t, success is
 defined by whether or not the conditional is still running after N
 seconds (as specified by the -n flag). In zero mode, -z, success is
 achieved when conditional exits with a return value of 0.
 The -n flag allows the interval to be set (in seconds) between
 successive attempts at running the conditional
 when will run until interrupted, or command completes.
OPTIONS
 -h Prints the help message and exits successfully.
 -n seconds
 Sets the interval for running the conditional to seconds
 In timebomb mode, the specified time in seconds will need to pass 
 before the conditional succeeds.
 -t Sets the success mode to timebomb which succeeds after
 conditional has been running for at least seconds
 -v Prints the version and exits successfully.
 -V Turns on verbose output. Mostly useful for debugging purposes.
 -z Sets the success mode to zero which succeeds after conditional
 returns 0 the first time. The conditional is guaranteed to be run
 at most 1 time every seconds
NOTE
 Note that both conditional and command are given to "sh -c" which
 means that you may need to use extra quoting to get the desired effect.
 Note that POSIX option processing is used (i.e., option processing
 stops at the first non-option argument). This means that flags
 after conditional don't get interpreted by when itself.
EXIT STATUS
 when makes an effort to exit with the exit status returned by the
 conditional in timebomb mode. In zero mode the exit status should be,
 well, 0.
EXAMPLES
 TODO more examples needed
 Suppose you have a failing build, xmessage will alert you when
 it succeeds.
 when "make" "xmessage 'hurrah, build passed'"
 Or you want to say hello to john when he logs on
 when "w | grep john" "echo 'hello, john' | write john"
 Or maybe you have a daemon failing in a tight loop due to
 misconfiguration or lack of resources. One can run it with when and
 be alerted to when it becomes happy
 when -n 10 -t "<failing daemon>" "xmessage 'daemon running'"
SEE ALSO
 watch(1)
COPYRIGHT
 Copyright (C) 2013 Andrew Gwozdziewycz
 This program is free software: you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published
 by the Free Software Foundation, either version 3 of the License,
 or (at your option) any later version.
 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 General Public License for more details.
 You should have received a copy of the GNU General Public License
 along with this program. If not, see <http://www.gnu.org/licenses/>
AUTHOR
 when was written by Andrew Gwozdziewycz <web@apgwoz.com> in 2013
 2013
 Dec
 10
 WHEN(1)