trr file format

Main Table of Contents	VERSION 4.0
GROMACS homepage	Sun 18 Jan 2009

Description

Files with the trr file extension contain the trajectory of a simulation. In this file all the coordinates, velocities, forces and energies are printed as you told GROMACS in your mdp file. This file is in portable binary format an can be read with gmxdump.

% gmxdump -f traj.trr

or if you're not such a fast reader:

% gmxdump -f traj.trr | more

You can also get a quick look in the contents of the file (number of frames etc.) using:

% gmxcheck -f traj.trr

http://www.gromacs.org