drush role-add-perm

Grant specified permission(s) to a role.

Drush Command

drush role-add-perm

role : The role to modify.  Required.

permissions : The list of permission to grant, delimited by commas. Required, unless the --module option is used.

drush rap

--module : Select the permission to modify from an interactive list of all permissions available in the specified module.

Allow anon users to post comments.

drush role-add-perm 'anonymous user' 'post comments'

Allow anon users to post comments and access content.

drush role-add-perm 'anonymous user' "'post comments','access content'"

Select a permission from "node" permissions to add to logged in users.

drush role-add-perm 'authenticated user' --module=node