in reply to Limit to Line Length?
There should be no limit to the length of a line.
OTOH there are a lot of subtle ways that file locking can go wrong, and most of the time when I see people offering advice on how to do it they get it wrong. Therefore, your confidence notwithstanding, I would suspect the locking routines.
For a discussion of what can go wrong, see RE: RE: Flock Subroutine or Don't use unflock (flock 8). Ever.. See Simple Locking for a reasonably good example of how to do it.
Incidentally if you can, I would suggest moving this to a database...
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