Clear Expired Shells In macOS

Recently, I got a strange message when trying to run a command:
You have exceeded the maximum number of shell sessions.
I’d seen a series of commands but never really needed to use them, so I ran: shell_session_delete_expired And viola, life was good. My command run. Of course, the next time I went to close the terminal correctly using the exit command. Upon doing so, I noticed:
logout Saving session… …copying shared history… …saving history…truncating history files… …completed. [Process completed]
screen-shot-2016-11-06-at-2-30-34-pm So, I opened a new shell and ran: shell_session_update And go the same result. Same with: shell_session_save Fun.