hardcopy plotting does NOT call fuser It isn't obviously needed (10 years ago I saw something that maybe said this was needed). And currently this generates lots of console chatter about "permission denied" accessing stuff completely unrelated to the plotting

new release 

feedgnuplot Debian release 1.63-1 

I explicitly ignore all lines that have '-' values These may come from vnl-filter -p "dx=diff(x)" ... output. For instance, this plot is broken before this patch: (echo '# x'; seq 5) | vnl-filter --noskipempty -p 'd=diff(x)' \ | feedgnuplot --lines

feedgnuplot Debian release 1.62-1 

changelog bump 

changelog bump 

version bump 

feedgnuplot Debian release 1.60-1 

version bump