This program is part of Netpbm.
pnmtorastreads a PPM image as input and produces a Sun rasterfile as output.
Color values in Sun rasterfiles are eight bits wide, so pnmtorast will automatically scale colors to have a maxval of 255. An extra pamdepth step is not necessary.
In addition to the options common to all programs based on libnetpbm (most notably -quiet, see Common Options), pnmtorast recognizes the following command line options:
All options can be abbreviated to their shortest unique prefix.
Forces the result to be in RT_STANDARD form.
Forces the result to be in RT_BYTE_ENCODED, which is smaller but, well, less standard.
The default is -rle.