. APPSPROD_linux.env (Source environment file)

The APPSPROD_linux.env is itself a source life. That is all that text in bracket is saying. That is for your information only. You dont have to enter that as part of the command.

The command you would enter would be like this:

. APPSPROD_linux.env

When you say I could not start the concurrent manger, what exactly that means? Are you getting errors etc?
Please run the above command to start the concurrent manager and post the output.

Or simply reboot the machine and start all services again. See if the concurrent manager comes up automatically. (You will be able to run the reports). If not then I would like to see the output of the above command.