Documentation
Quantum ESPRESSO Hands-on Tutorial (Graphene)
Common Questions for Beginners

Common Questions for Beginners

Questions

1. How can I run pw.x without typing the full path (/home/.../pw.x)?

At first, you may need to run QE using the full path:

mpirun -np 16 /home/hwang/q-e-qe-7.4.1/bin/pw.x -in ausurf.in > ausurf.out

You can set it up so that only pw.x is needed:

mpirun -np 16 pw.x -in 1scf.in > 1scf.out

Setup

  1. Run the following commands once:
echo 'export PATH="/home/hwang/q-e-qe-7.4.1/bin:$PATH"' >> ~/.bashrc
source ~/.bashrc
  • The first command, echo ... >> ~/.bashrc, adds the Quantum ESPRESSO bin path to your ~/.bashrc file.
  • The second command, source ~/.bashrc, reloads .bashrc and applies the setting immediately to the current terminal.
  1. Then check that pw.x can be found:
which pw.x
  1. It should return something like:
/home/hwang/q-e-qe-7.4.1/bin/pw.x
  1. You can now use this command:
mpirun -np 16 pw.x -in 1scf.in > 1scf.out

What is this setting called?

This is called adding a directory to the PATH environment variable. PATH tells Linux where to look for executable programs.

Because the setting is saved in ~/.bashrc, it is automatically applied to future Bash sessions.

Note: If you run only

export PATH="/home/hwang/q-e-qe-7.4.1/bin:$PATH"

in the terminal without adding it to ~/.bashrc, it applies only to the current shell session.