You can try Quantum Package in the terminal below. To configure the terminal for your favorite text editor, set the `EDITOR` environment variable:

    export EDITOR=vim

Here is an example of a few commands you can run to get the Full-CI energy of the HCN molecule.

First create a file named `hcn.xyz` containing the xyz coordinates.

    $ cat << EOF > hcn.xyz
    3
    HCN molecule
    C    0.0    0.0    0.0
    H    0.0    0.0    1.064
    N    0.0    0.0    -1.156
    EOF

Create the EZFIO database as follows:

    qp create_ezfio -b 6-31g hcn.xyz -o hcn

Run a Hartree-Fock calculation:

    qp run SCF | tee scf.out

The MOs are saved in the EZFIO database. Now freeze the core electrons:

    qp set_frozen_core

And run the CIPSI calculation in the valence full CI space:

    qp run fci | tee fci.out

That’s it!

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