Changing wordpress theme to default theme via command line

Log in to mysql server and issue the command :

SELECT * FROM wp_options WHERE option_name = 'template' OR option_name = 'stylesheet' OR option_name = 'current_theme';

UPDATE wp_options SET option_value = 'twentyeleven' WHERE option_name = 'template' or option_name = 'stylesheet' or option_name = 'current_theme';