The s6-ftrig-wait program

s6-ftrig-wait subscribes to a fifodir and waits for a pattern of events to occur on this fifodir.

Interface

     s6-ftrig-wait [ -t timeout ] fifodir regexp

s6-ftrig-wait subscribes to fifodir
It waits for the series of events received on fifodir to match regexp. regexp must be an extended regular expression.
When the series of read events matches regexp, s6-ftrig-wait prints the last event it received (one byte) to stdout, then exits 0.

-t timeout : if the events on fifodir have not matched regexp after timeout milliseconds, print an error message on stderr and exit 1. By default, s6-ftrig-wait waits indefinitely for a matching series of events.