Michael ODonnell wrote:
...tail -f...I have yet to see any output when used
on the RHEL3 system where I actually need to do the filtering.
Try -F. Quoting tail(1):
-F same as --follow=name --retry
--retry keep trying to open a file even when it is or becomes
inaccessible;
Some years back I created a little FIFO-reader utility that can be
used to relay data via a named pipe (FIFO) such that it keeps the
output end of the FIFO open despite multiple opens/closes of the
input end by one or more writers.
This is necessary because the naive approach only works once, as
Well... interesting. I wonder why cat acts that way. Interestingly, I'd
played around with FIFOs some time ago, and there's a fine way to cheat:
tail -f.
k...@minastirith:~$ mknod /tmp/FIFO p
k...@minastirith:~$ tail -f /tmp/FIFO /tmp/FIFO.log
[1] 13082
k...@minastirith:~$ date /tmp/FIFO
Michael ODonnell writes:
I'm now working with a cantankerous old app that can't easily be
modified and it'd be handy to have multiple sequential invocations of
that app each spew some logging data into a FIFO (without blocking)
so it could be processed by a single persistent instance of a
Ken wrote:
Well... interesting. I wonder why cat acts that way.
IIRC a read() of the FIFO when all data have been consumed and the
writer has closed his end yields -1 with errno EAGAIN and most apps
just call it quits at that point.
Interestingly, I'd played around with FIFOs some time
Interestingly, I'd played around with FIFOs some time ago, and
there's a fine way to cheat: tail -f.
D'oh!!!
It might be coming back to me now, why I didn't use the tail -f
trick Way Back When; although it appears to work as expected with
a FIFO on a CentOS5.4 box I have yet to see any
