nyx-shell

A POSIX-compatible interactive shell written entirely in Nyx (~1175 lines, single file). Demonstrates Nyx's process control builtins (fork, execvp, waitpid, dup2, pipe) with no FFI or C glue code.

Shell interactivo compatible con POSIX escrito completamente en Nyx (~1175 líneas, archivo único). Demuestra los builtins de control de procesos de Nyx (fork, execvp, waitpid, dup2, pipe) sin FFI ni código C adicional.

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Install

Install the Nyx toolchain:

curl -sSf https://nyxlang.com/install.sh | sh

Quick start

git clone https://github.com/nyxlang-dev/nyx-shell
cd nyx-shell
nyx build
./nyx-shell

Usage

./nyx-shell                        # interactive mode
./nyx-shell -c "ls -la"            # run a single command
echo "cmd1 | cmd2" | ./nyx-shell   # pipe mode (non-interactive)
nyx shell                          # via Nyx wrapper

Features

• External commands: PATH lookup + fork + execvp + waitpid
• Pipes: cmd1 | cmd2 | cmd3 — arbitrary pipeline length
• Redirects: >, >>, <
• Conditionals: && (run on success), || (run on failure)
• Variable expansion: $VAR, ${VAR}, $? (last exit code), $$ (PID)
• Tilde expansion: ~/path → $HOME/path
• Quoted strings: "interpolated" and 'literal $no-expand'
• Persistent history: saved across sessions to ~/.nyx_history
• Raw mode line editor: inline editing with arrow keys and cursor movement

Builtins

Command	Description
cd [dir]	Change directory (cd alone goes to $HOME)
pwd	Print working directory
echo [args...]	Print arguments to stdout
export VAR=value	Set environment variable
unset VAR	Remove environment variable
type cmd	Show whether command is builtin or external (with path)
history	Show command history
exit [code]	Exit shell (default code: 0)

Keybindings

Key	Action
Up / Down	Navigate history
Left / Right	Move cursor in line
Home / Ctrl+A	Move to start of line
End / Ctrl+E	Move to end of line
Ctrl+K	Delete from cursor to end of line
Ctrl+U	Delete from start of line to cursor
Ctrl+W	Delete previous word
Ctrl+L	Clear screen
Ctrl+C	Cancel current line
Ctrl+D	Exit shell (on empty line)
Backspace	Delete previous character
Delete	Delete character at cursor

Documentation

Internal architecture and implementation notes: docs/README.md

Limitations

• No job control (bg, fg, Ctrl+Z)
• No filename globbing (*.txt)
• No heredocs (<<EOF)
• No command substitution ($() or backticks)
• No arithmetic expansion ($((...)))

License

Apache 2.0 — see LICENSE