Q: applet flock fails with 'invalid number $filename'

[Johannes Stezenbach]

On Wed, Jan 06, 2016 at 11:37:33PM -0800, Isaac Dunham wrote:
> 
> If you want to run it to lock a critical section of a script, use
> exec FD>> FILE
> flock FD
> ...
> flock -u FD

FWIW, I think canonical use is:

   {
	flock 9
	...

   } 9>$lockfile


Johannes