Here's yet another way, demonstrated from the shell:

Make the pipe, and...

$ mkfifo logpipe
$ perl -e 'open PIPE, "< logpipe"; { select 1<<fileno(PIPE),undef,unde
+f,undef; print <PIPE>;redo}' &
[download]

... start a simple server in the background. select makes it sleep till PIPE is readable. redo in a bare block loops forever. Kick the tires:

$ echo foo >logpipe
foo
$ echo far >logpipe
$ far

echo fie >logpipe
fie
$
[download]

The asynchronous operation of the server is shown in the staggered output. Clean up with

$ fg
perl -e 'open PIPE, "< logpipe"; {select 1<<fileno PIPE,undef,undef,un
+def;print <PIPE>;redo}'
# do a Ctrl-C here
$
[download]

I think this is the Right Way® to handle your log file problem. Sleeping till there is something to read will save a lot of load on the host.

Update: Changed to use mkfifo instead of mknod, and repaired a pasto in the timeout arg of select.

After Compline,
Zaxo

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