Provided by: netpbm_10.0-15.3build1_amd64
pbmtoascii - convert a portable bitmap into ASCII graphics
pbmtoascii [-1x2|-2x4] [pbmfile]
Reads a portable bitmap as input. Produces a somewhat crude ASCII graphic as output. Note that there is no asciitopbm tool - this transformation is one-way.
The -1x2 and -2x4 flags give you two alternate ways for the bits to get mapped to characters. With 1x2, the default, each character represents a group of 1 bit across by 2 bits down. With -2x4, each character represents 2 bits across by 4 bits down. With the 1x2 mode you can see the individual bits, so it's useful for previewing small bitmaps on a non-graphics terminal. The 2x4 mode lets you display larger bitmaps on a standard 80-column display, but it obscures bit-level details. 2x4 mode is also good for displaying graymaps - "pnmscale -width 158 | pgmnorm | pgmtopbm -thresh" should give good results.
Copyright (C) 1988, 1992 by Jef Poskanzer. 20 March 1992 pbmtoascii(1)