I am currently doing parallel cascade simulations in GROMACS 4.6.5 and I am inputting the commands using a bash script:
#!/bin/bash
pdb2gmx -f step_04_01.pdb -o step_04_01.gro -water none -ff amber99sb -ignh
grompp -f minim.mdp -c step_04_01.gro -p topol.top -o em.tpr
mdrun -v -deffnm em
grompp -f nvt.mdp -c em.gro -p topol.top -o nvt.tpr
mdrun -v -deffnm nvt
grompp -f md.mdp -c nvt.gro -t nvt.cpt -p topol.top -o step_04_01.tpr
mdrun -v -deffnm step_04_01
trjconv -s step_04_01.tpr -f step_04_01.xtc -pbc mol -o step_04_01_pbc.xtc
g_rms -s itasser_2znh.tpr -f step_04_01_pbc.xtc -o step_04_01_rmsd.xvg
Commands such as trjconv and g_rms require user interaction to select options. For instance when running trjconv you are given:
Select group for output
Group 0 ( System) has 6241 elements
Group 1 ( Protein) has 6241 elements
Group 2 ( Protein-H) has 3126 elements
Group 3 ( C-alpha) has 394 elements
Group 4 ( Backbone) has 1182 elements
Group 5 ( MainChain) has 1577 elements
Group 6 ( MainChain+Cb) has 1949 elements
Group 7 ( MainChain+H) has 1956 elements
Group 8 ( SideChain) has 4285 elements
Group 9 ( SideChain-H) has 1549 elements
Select a group:
And the user is expected to enter eg. 0 into the terminal to select Group 0. I have tried using expect and send, eg:
trjconv -s step_04_01.tpr -f step_04_01.xtc -pbc mol -o step_04_01_pbc.xtc
expect "Select group: "
send "0"
However this does not work. I have also tried using -flag like in http://www.gromacs.org/Documentation/How-tos/Using_Commands_in_Scripts#Within_Script but it says that it is not a recognised input.
Is my expect \ send formatted correctly? Is there another way around this in GROMACS?
I don't know gromacs but I think they are just asking you to to use the bash syntax:
yourcomand ... <<EOF
1st answer to a question
2nd answer to a question
EOF
so you might have
trjconv -s step_04_01.tpr -f step_04_01.xtc -pbc mol -o step_04_01_pbc.xtc <<EOF
0
EOF