High Quality Content by WIKIPEDIA articles! gretl is an open-source statistical package, mainly for econometrics. The name is an acronym for Gnu Regression, Econometrics and Time-series Library. It has a graphical user interface and can be used together with X-12-ARIMA, TRAMO/SEATS, R, Octave, and Ox. It is written in C, uses GTK as widget toolkit for creating its GUI, and uses gnuplot for generating graphs. As a complement to the GUI it also has a command line interface.