Revisiting ⎕SH and ⎕CMD - Exploring Limitations and New System Functions

Explore the limitations and potential improvements of using ⎕SH and ⎕CMD to run commands through the operating system's shell in this 18-minute conference talk from Dyalog '23. Delve into various use cases, including grep and cat examples, while examining current constraints such as error output handling, input management, and slow command execution. Learn about a proposed new system function designed to overcome these limitations, offering enhanced control over input/output redirections. Discover how to specify arguments, variant options, environment variables, and redirections with this new function. Gain insights into default redirections and see practical examples of how this improved functionality can be applied to common tasks like cat and tr commands.

Introduction
Use cases
grep example
cat example
Current limitations
Error output
Input
Slow commands
Output before error
Non-text output
Environment variables
A new system function
Argument specification
Variant options
Specifying environment variables
Specifying redirections
Specifying redirection targets
Specifying redirection sources
Default redirections
cat example revisited
tr example
Conclusion