Rules for how Drush vset works
On administration forms system_settings_form is normally used to return form,
so the element id is same as the variable name without the "#edit-" with underscores.

For example on: /admin/config/system/site-information 

id="edit-site-mail" -&gt; drush vset site_mail peter@email.com


To turn off the email verification:

"edit-user-email-verification" -&gt; drush vset user_email_verification 1


Drush returns all variables that match with your variable name, so if you only know part of the name you can try:

drush vget email


returns all matches:

user_mail_status_canceled_notify: 0
user_mail_status_canceled_subject: "Account details for [user:name] at [site:name] (canceled)"
reroute_email_address: "debug@email.net"
reroute_email_enable: "TRUE"


Module devel (https://drupal.org/project/devel) let you check all drupal variables on this menu callback: /devel/variable