Rash: from reckless interactions to reliable programs

Abstract

Command languages like the Bourne Shell provide a terse syntax for exploratory programming and system interaction. Shell users can begin to write programs that automate their tasks by simply copying their interactions verbatim into a script file. However, command languages usually scale poorly beyond small scripts, and they can be difficult to integrate into larger programs. General-purpose languages scale well, but are verbose and unwieldy for common interactive actions such as process composition. We present Rash, a domain-specific command language embedded in Racket. Rash provides a terse and extensible syntax for interactive system administration and scripting, as well as easy composition of both Racket functions and operating system processes. Rash and normal Racket code can be nested together at the expression level, providing the benefits of a shell language and a general-purpose language together. Thus, Rash provides a gradual scale between shell-style interactions and general-purpose programming.