pgmhist
Print a histogram of the values present in a PGM image.
TLDR
Display the histogram for human reading
$ pgmhist [path/to/image.pgm]
Display the median grey value
$ pgmhist -median [path/to/image.pgm]
Display four quartile grey value
$ pgmhist -quartile [path/to/image.pgm]
Report the existence of invalid grey values
$ pgmhist -forensic [path/to/image.pgm]
Display machine-readable output
$ pgmhist -machine [path/to/image.pgm]
