New port: shells/yash
Yash, yet another shell, is a POSIX-compliant command line shell.
Yash is intended to be the most POSIX-compliant shell in the world
while supporting features for daily interactive and scripting use.
Notable features are:
- Global aliases
- Socket redirection, pipeline redirection, and process redirection
- Brace expansion and extended globbing
- Fractional numbers in arithmetic expansion
- Prompt command and command-not-found handler
- Command line completion with predefined completion scripts for more than 100 commands
- Command line prediction based on command history