Sometimes you need to do a tail -f, grep the results, and
then nuke the file and start all over again... wouldn't it
be nice if you could just run a single command to do it, and
optionally have it serve the output up on a port?

Hotgrep does just that! And the file can be deleted, moved,
recreated, truncated... all during a single hotGrep session.

Example command line:
   
   hotgrep /that/file/over.there '.+' 3

Which will ''tail -f'' the file, returning all new lines,
and checking every 3 seconds for new data.

Argument 1 is the filename.

Argument 2 is the regexp pat applied to lines, only lines that match are returned.

Argument 3 is the delay in seconds between updates (if not provided defaults to 2 seconds).

Argument 4, if provided, is the port to run the server on.

UNIX only.

http://inferno.slug.org/cgi-bin/wiki/hotGrep

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[AM] There is a ActiveState cookbook receipe that shows how to emulate "tail -f" in Tcl. Combining that with hotGrep would provide a platform-independent solution.