How to use pbm2lpbm

[bcarter]

I have a valid .pbm P4 image.

I've tried to run pbm2lpbm several ways that don't work.

1. ./pbm2lpbm myfile.pbm
2. ./pbm2lpbm $(cat myfile.pbm)
3. cat myfile.pbm | ./pbm2lpbm
4. cat myfile.pbm | pbm2lpbm

I finally got it working with this command.
./pbm2lpbm < myfile.pbm > myfile.lpbm

Is this the best way to call it?

I don't know c well enough to make a change but I think the first option above would be the most obvious. Pass in the filename to be converted and it automatically makes a new .lpbm file with the same name.