pnmhistmap
Draw a histogram of a PNM image. tldr-pages
On several platforms
Several platforms
Draw a histogram of a PNM image
pnmhistmap path/to/input.pnm >path/to/output.pnmIdentifyDraw the histogram as dots instead of bars
pnmhistmap -dots path/to/input.pnm >path/to/output.pnmIdentifySpecify the range of intensity values to include
pnmhistmap -lval minval -rval maxval path/to/input.pnm >path/to/output.pnmIdentify