ppmhist
Display color histogram of PPM images
TLDR
Show color histogram
$ ppmhist [input.ppm]
Show as map file$ ppmhist -map [input.ppm]
Limit output colors$ ppmhist -noheader [input.ppm] | head -20
SYNOPSIS
ppmhist [options] [file]
DESCRIPTION
ppmhist reads a PPM (Portable Pixmap) image and prints a color histogram showing each distinct color and the number of pixels using it. It is part of the Netpbm toolkit and is useful for analyzing palette usage, identifying dominant colors, and preparing colormaps for quantization.By default the output is a sorted text table. With -map, the output is itself a valid PPM file representing the colormap, which can be fed to other Netpbm tools.
PARAMETERS
-map
Output a colormap as a PPM file rather than a text table.-nomap
Force text histogram output (the default).-noheader
Omit the leading header line from text output.-sort method
Sort entries by frequency or rgb.
INSTALL
sudo apt install netpbm
sudo dnf install netpbm
sudo pacman -S netpbm
sudo apk add netpbm
sudo zypper install netpbm
brew install netpbm
nix profile install nixpkgs#netpbm
SEE ALSO
pgmhist(1), pnmcolormap(1), ppmtopgm(1)