RT: Regular Types for the Streaming Shell
Talkat 20th USENIX Symposium on Operating Systems Design and Implementation (OSDI '26) · 2026-07-13..07-15·
summary
RT is an overlay type system that statically checks shell pipelines by modeling command input/output as regular types and reducing composition to regular-language inclusion. The prototype type checker analyzes 954 real programs from StackOverflow, GitHub, and benchmarks, runs in 0.02s average, finds composition bugs like numeric-sort and xargs word-splitting, achieves 91% accuracy for serious bugs (72% auto, 94% with a few annotations) and 98% precision on correct scripts.
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chapters (12)
- 0:00Introduction to RT
- 1:23Unix shell pipeline bugs
- 3:29ShellCheck limitations
- 4:10RT's type system
- 5:16Types as regular languages
- 6:19Command compatibility limits
- 8:27RT built-in types
- 11:21Polymorphic types for commands
- 12:44Catching word-splitting bugs
- 13:47Non-regular data handling
- 15:12RT evaluation
- 16:56RT vs ShellCheck summary
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