catdcd of vmd

Dear Axel,
Using catdcd (below command) I am trying to concatenate a series of gromacs gro files to generate a .trr trajectory out of them;

~ catdcd -o traj.trr -otype trr -gro f1.gro f2.gro f3.gro f4.gro f5.gro
The command runs with no error and it can read the f*.gro files, but no frame is is being added to the trajectory.
Would you please let me know where I am doing wrong?

Thank you
Henrik

Please ask questions about VMD on the VMD mailing list.
Axel

Dear Henrik,
Why do not you use gmx trjcat for the concatenation.