[gmx-users] Choose index group from terminal input.

[Dawid das]

Dear Gromacs Experts,

Let's say that for some reasons I don't want to specify the atom group when
g_rms (or other module) prompts me to do so.
So I do not want to see this:

Select group for RMSD calculation
Group     0 (         System) has 38387 elements
Group     1 (        Protein) has  3470 elements
Group     2 (      Protein-H) has  1772 elements
Group     3 (        C-alpha) has   217 elements
Group     4 (       Backbone) has   653 elements
Group     5 (      MainChain) has   869 elements
Group     6 (   MainChain+Cb) has  1065 elements
Group     7 (    MainChain+H) has  1076 elements
Group     8 (      SideChain) has  2394 elements
Group     9 (    SideChain-H) has   903 elements
Group    10 (    Prot-Masses) has  3461 elements
Group    11 (    non-Protein) has 34917 elements
Group    12 (          Water) has 34845 elements
Group    13 (            SOL) has 34845 elements
Group    14 (      non-Water) has  3542 elements
Group    15 (            Ion) has    72 elements
Group    16 (             NA) has    37 elements
Group    17 (             CL) has    35 elements
Group    18 ( Water_and_ions) has 34917 elements
Group    19 (    Chromophore) has    37 elements
Select a group: 1
Selected 1: 'Protein'

and I want to specify this Group 1 (Protein) in my command, e.g.
g_rms -s ../npt-md2.tpr -f ../npt-md2.xtc -tu ns -b 0 -e 100 -n
../index.ndx -o rmsd-0-100.xvg
-some_option 1
Is it possible?