Convert a PBM image to a X11 or X10 bitmap.
Convert a PBM image to a X11 XBM file
pbmtoxbm path/to/input_file.pbm > path/to/output_file.xbm
Explicitly specify whether an X11 or X10 bitmap should be generated
pbmtoxbm -x11|x10 path/to/input_file.pbm > path/to/output_file.xbm