#/bin/perl/

use strict;

#test only for file 1M01_F00121.npt.gro
my $file = /(1M01)(\_)(F)(\0+)(121)/;

print $file; # for testing
  
`grompp -f input.mdp -c "$file".npt.gro -p topol.top -o "$file".md.tpr`; 



##</code><code>##

 #/bin/perl/

use strict;

my $i;

#now loop through all the files in the directory
for ($i=121; $i<=150; $i++) {
 
my $file = /(1M01)(\_)(F)(\0+)($i)/;

print $file; # for testing
 
`grompp -f input.mdp -c "$file".npt.gro -p topol.top -o "$file".md.tpr`;

}