[Kst] how to filter "live" data

[Dan Field]

Hi folks:

I would like to generate plots from a constantly changing log file.  The
problem is that there are different record types in this file and I'm
only interested in graphing a particular type.  The records in which I'm
interested can be selected based upon the first N characters of the
record so a simple grep expression like ^<prefix> would suffice.

I know I can grep the log file and send it to a different log file which
kst reads, but then updates only occur when the grep program decides to
flush its output.  Is there some sort of filter within kst that allows
me to exclude records from the data?

Best,
    Dan