pnmtorast

Convert a PNM file to a Sun rasterfile. More information: https://netpbm.sourceforge.net/doc/pnmtorast.html.

pnmtorast path/to/input.pnm > path/to/output.rast

pnmtorast -standard|rle path/to/input.pnm > path/to/output.rast