How can I tell when my text file is busy?

[M. G. Hand]

Before the tirades of abuse start to arrive...   The note about /etc/install
I posted to the net this morning.  The comment i wrote about security
considerations was caused by my confusing what is preserved and what is
changed under certain conditions.  I was thinking that set uid bit in the
mode would be preserved while the user would be changed to bin. Of course,
the mode 755 change and change to bin go han in hand.  Oops, sorry.
		marcus hand (pyuxt!marcus)