[gmx-users] gmx trjcat

[Alex]

Dear all,
I want to concatenate some gro file to have a trr or xtc trajectory file
out of them as gro files are also acceptable as input files, according the
gmx trjcat man page;

Options to specify input files:
 -f      [<.xtc/.trr/...> [...]] (traj.xtc)
           Trajectory: xtc trr cpt *gro* g96 pdb tng

So, I fed the .gro files in as input files likes;
gmx trjcat -f c*.gro -o trajout.trr

However, I get below error that;
Fatal error:
gmx trjcat can only handle binary trajectory formats (trr, xtc, tng)

Any comment is highly appreciated.
Regards,
Alex