TIBCO Enterprise Administrator(TEA) has two command line option to perform tasks TIBCO Enterprise Administrator(TEA) shell and Python script.

 
Currently  the use of  RSA key to login to TIBCO Enterprise Administrator(TEA) shell is not supported. Users have to use username/password to login to TEA Shell.
We have an enhancement request for the same TEA-2933. 

Alternate method is to use python script. Below are a sample statements to register EMS agent and add EMS server to TEA
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>>> import tibco.tea
>>> tea = tibco.tea.EnterpriseAdministrator( url='http://sthuthik-dt:8777', user='admin', pwd='admin' )
>>> tea.agents.registerAgent('EMS','http://localhost:8077/ems','ems registered using python script')
>>> ems1 =tea.products['EMS']
>>> ems1.registerEmsServer('serverName', 'URL', 'userName','password')
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