The objective of this snippet is to teach you how to change the theme of your portal through Drush with vset. This snippet is useful enough when you have to restore the theme from zero or change it to another, when you can’t do it with its own interface.
# Show current drupal default and admin theme.
drush status theme
# Change admin default theme to garland.
drush vset admin_theme garland
# Change site default theme to garland.
drush vset theme_default garland