Purpose
Loop until a new "cam*.fits" image appears in the nightly directory,
and return the name of the image
Usage
wftv [-silent]
Arguments
-silent = do not echo the name of the TV image
Output
Name of the TV image is echoed to STDOUT
Restrictions
None
Exit values
0 = normal completion
1 = wrong number of arguments
Example
1) Wait for a new TV image to appear and echo the name
wftv
2) Wait for new TV image to appear and silently return
wftv -silent