head.x command not found

In this troubleshooting guide we learn how to fix head.x command not found error message

Introduction

When you run more command in linux terminal / console, you get the following error message

head.x: command not found

or when using sudo you get the following error message

sudo: head.x: command not found

Solutions to head.x: command not found

How To Fix head.x: command not found in Ubuntu / Debian / Kali Linux / Raspbian

In Ubuntu head.x is provided by quantum-espresso package.

quantum-espresso is:

Quantum ESPRESSO (formerly known as PWscf) is an integrated suite of computer codes for electronic-structure calculations and materials modeling at the nanoscale. It is based on density-functional theory, plane waves, and pseudopotentials (both norm-conserving, ultrasoft, and PAW).

Features include:

  • Ground-state single-point and band structure calculations using plane-wave self-consistent total energies, forces and stresses
  • Separable norm-conserving and ultrasoft (Vanderbilt) pseudo-potentials, PAW (Projector Augmented Waves)
  • Various exchange-correlation functionals, from LDA to generalized-gradient corrections (PW91, PBE, B88-P86, BLYP) to meta-GGA, exact exchange (HF) and hybrid functionals (PBE0, B3LYP, HSE)
  • Car-Parrinello and Born-Oppenheimer Molecular Dynamics
  • Structural Optimization including transition states and minimum energy paths
  • Spin-orbit coupling and noncollinear magnetism
  • Response properties including phonon frequencies and eigenvectors, effective charges and dielectric tensors, Infrared and Raman cross-sections, EPR and NMR chemical shifts
  • Spectroscopic properties like K- and L1-edge X-ray Absorption Spectra (XAS) and electronic excitations

To fix this problem, we can install more using the command below.

sudo apt-get -y install quantum-espresso

This command might take some time to finish depending on your machine internet connection.

You can also use apt command to install quantum-espresso.

sudo apt -y install quantum-espresso

Or if you have aptitude installed you can use the following command.

sudo aptitude install quantum-espresso

Summary

In this tutorial we learn how to fix head.x command not found error in Ubuntu / Debian / Kali Linux or Raspbian distribution.