code: function checkUnix(directoryPath) {
    if (!path.normalize(directoryPath).startsWith(path.sep)) {
      return new Promise((resolve, reject) => {
        reject(new InvalidPathError(`The following path is invalid (should start by ${path.sep}): ${directoryPath}`))
      })
    }
  
    return check(
      `df -Pk "${module.exports.getFirstExistingParentPath(directoryPath)}"`,
      () => true, // We should only get one line, so we did not need to filter
      {
        diskPath: 5,
        free: 3,
        size: 1
      },
      1024 // We get sizes in kB, we need to convert that to bytes
    )
  }
docs: Build the check call for unix
  
  @param {String} directoryPath - The file/folder path from where we want to know disk space
  @return {Promise} -