Session managers save the current state of open audio applications along with their connections, allowing sessions to be easily restored without having to manually open each application, load individual settings files, and reconnect all JACK connections.
There are several session managers available for Linux. However, not all applications are compatible with all session managers, though some managers do provide limited support for apps not designed to work with that particular session manager.
These are some of the most well-known session managers available for Linux, in order of historical appearance.
Quite a few folks are using scripts with tools developed for this purpose.
A selection of links providing further information about Linux audio session management.
ladish-0.2 demonstration video
Creating a simple LADISH studio using Claudia
The Penguin Producer: The LADI Session Handler
Linux Weekly News: A Brief Survey of Linux Audio Session Managers by Dave Philips (January 2013)