What is the imperative form of ‘daashtan’ داشتن ?

As a simple verb and for most compound verbs with it, the subjunctive past form is used:

Daashtebaash! داشته باش ‘Have it!’ // E’temaad daashtebaash! اعتماد داشته باش ‘Have trust!’ // Ettelaa’ daashtebaash! اطّلاع داشته باش ‘Be informed!’

For prefixal verbs and some compound verbs, the subjunctive present form is used:

Bar-daar! بردار ‘Pick it up!’ // Negah daar! نگه دار ‘Keep it!’ // Ersaal daarid!ارسال دارید ‘Send!’.