This command enables you to grant or revoke any permission on an app. This is the same as changing Settings > App > (your app) > Permissions.
An app will usually ask for it’s required permissions on demand or when it’s launched for the first time. With this, you can grant those permissions beforehand.
To grant all permissions that a apps has defined, use "all" as the App permission value
Example: We allow the app with the package name “com.handheldgroup.someapp” to read the phone contacts