Before you use cassub to submit a JCL job on your machine, you must already have started the enterprise server using casstart.
If the enterprise server does not have a batch initiator SEP defined that handles jobs of the same class as the job you want to submit, you must also start a suitable batch initiator SEP using the command casout.
casstart -rjcldemo cassub -j/var/mfcobol/es/jcldemo/esjcl/esjcl.jcl -rjcldemo
This submits the JCL in the file /var/mfcobol/es/jcldemo/esjcl/esjcl.jcl to the enterprise server jcldemo.