Modelling as Shell Programming: Concurrency and Delegation

We show how to build and execute models of concurrent and distributed production systems using some of the Unix tools for text processing (Awk), process management (Bash) and information exchange (Mail). We use plain text files to represent the state of the production cell, implement production operations as text-transformations, compose such operations into one or several processes for their sequential or concurrent execution and allow remote processes (located in different cells) to communicate with each other by sending emails. The models are highly configurable, able to represent assembly lines, flexible manufacturing systems, even virtual organisations. But they are also concrete and implementation-dependent, therefore we also present their abstract formalisation in a specification language RSL.