# Quick Start Guide

Critic2 reads the user commands from a single input file (the .cri file). A simple input is:

crystal cubicBN.cube
yt


which reads the crystal structure from a cube file (cubicBN.cube), then the electron density from the same cube file, and then calculates the atomic charges and volumes using the YT method. Critic2 accepts many structure and density/scalar field formats written by quantum chemistry software (see the manual for more info).

To run critic2, do:

critic2 cubicBN.cri


This will write to the standard output. Redirect the output to a file with either of:

critic2 cubicBN.cri > cubicBN.cro
critic2 cubicBN.cri cubicBN.cro


Finally, you can just open critic2 and type commands by hand:

critic2
\$ ...


If you do this, it is best to compile critic2 with readline support or use the rlwrap program:

rlwrap critic2


Either option will provide command history, emacs-style key bindings, and autocompletion features, and make the interactive usage of critic2 much easier,

A detailed description of the critic2 keywords is given in the user’s guide and a list of commands in the syntax.