yui

A simple and minimal UNIX shell inspired by Bash and Fish, written in pure Rust utilizing rustyline, a Rust alternative to GNU readline.

yui is primarily interactive focused, although it does have a small parser for light scripting. I wrote it mainly to help me learn Rust, and the basics of interfacing and managing UNIX processes.

It is currently highly experimental and probably shouldn't be used as a daily driver yet.

To build

You will need:

• rustc
• cargo

Clone the repo:

git clone https://github.com/rayes0/yui.git
cd yui

If you just want to try yui (dev version):

cargo run

Building:

cargo build --release

Configuration

A sample config file is provided in the examples directory. For full documentation, see https://github.com/rayes0/yui/wiki/Configuration

Features (Current and Planned)

Click to expand!

• Documentation

Core

• Run basic commands with args
• Quoted strings: "" and ''
• Simple signal handling
• Exit code handling
• ~ expansion for homedir
• Comprehensive bash-like history expansion:
  • !! history expansion
  • bash-like "magic space"
  • history expansion by both relative and absolute index
  • Advanced expansion with globbing: !*, !$, !^
  • Reverse history search
• Differentiate between login and non login shell
• Job control
  • jobs, bg and fg builtins
  • CTRL-Z
• Run command with temporary environment, eg: PATH=/bin ls
• Run command from another directory without need for cd into it first

Editing

• Utilize vi or emacs modes to edit lines
• Support for multi-line commands (with \)
• Support using external editor to edit commands
• Option for inline alias, variable, and history expansion

Parser

• small parser for light scripting only, mainly to make the config somewhat bashrc-like (partly finished)
  • Full line comments starting with #
  • Partial line comments
  • if conditionals
• functions

Operators and Syntax

• test, [, and ] for testing conditionals
  • ==, !=, <, >
• AND and OR: && and ||
• End of command: ;
• Basic arithmetic: +, -, /, *, %
  • Follow order of operations
  • Float calculations
• Pipes via |
• Redirections via > and <
• \ for escaping characters
• Support for globs: *, [...], ?, {...} etc.
• Command substitution (subshells?) through $() and backticked strings

Builtins

• echo
  • Print basic text
  • Support printing styled text
  • Support same flags as bash's builtin version
• cd
• exit
  • Specify custom exit code
• history
• alias
• exec
• export (env vars)
• bind, to create custom keybinds
• set, to change settings on the fly

Completion and Hinting

• toml files or similar for custom completions
• Directory and file completions
• Command completions
• Automatic completion hinting from history
  • Intelligent hinting according to cwd
• Host completion for ssh

Customization

• Read settings from configuration file
• Optional truecolor support
• Simple prompt customization

Won't do (Things that will not be implemented into yui, at least for the time being):

• for, while, until, etc. Any kind of looping - use a proper scripting language for that
  • "What! No for loops?!!. What if I need to loop over a directory of files?" - Use proper tools meant for that (eg: GNU find)
• Advanced arithmetic, precision above 8-9 digits, trigonometry, etc. - use an appropriate tool for that
• Advanced/special expansions: $$, ${foo/foo/bar}, ${foo##.*}, etc. - You should probably be using a proper scripting language if you need these

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For those wondering, yes, it is named after the character Yui Hirasawa from the K-ON! series.