Install ruby-pgplot by entering the following commands in the terminal:
sudo apt update sudo apt install ruby-pgplot
Description:
Ruby interface to the PGPLOT graphics library
Ruby/PGPLOT is the Ruby interface to the PGPLOT graphics library. PGPLOT is a FORTRAN library to draw line/scatter/histogram plot, error bar, contour/image/vector map, etc. Supports various output devices including Postscript, PNG, X-Window, etc.
Homepage: http://pgplot.rubyforge.org/
Version: 0.1.9-3build2
Section: multiverse/ruby