odin-shell

Implementing a zsh shell from scratch in Odin.

NOT AI SLOP

AI has NOT been used to implement any piece of this code. AI has been used only to review the codebase. All implementation, architecture, design, debugging, etc... has been done by a human.

Features

Builtin Commands

• echo, type, pwd, cd, exit, history

Command Execution

• External program execution via PATH lookup
• Process forking with fork/execvp
• Exit code tracking ($? semantics)

Parsing & Quoting

• Single and double quote handling with escape sequences
• Backslash escaping outside quotes
• Semicolon (;) command chaining
• Brace parsing with error detection

I/O Redirection

• Stdout redirection (>, >>, 1>, 1>>)
• Stderr redirection (2>, 2>>)
• Stdin redirection (<)

Pipelines

• Multi-command pipelines (cmd1 | cmd2 | cmd3)
• Proper pipe fd management and per-stage forking
• Exit code from last pipeline stage (zsh semantics)

Expansions

• Tilde expansion (~, ~/path, ~user)
• Brace expansion — comma lists ({a,b,c})
• Brace expansion — numeric ranges ({1..10}, {01..05}, {1..10..2})
• Brace expansion — alphabetic ranges ({a..z})
• Nested brace expansion

Tab Completion

• Command name completion (builtins + PATH executables)
• File and directory path completion
• Longest common prefix completion
• Double-tab to list all matches

History

• Arrow key (up/down) history navigation
• HISTFILE persistence (load on start, append on exit)
• history builtin with -w, -a, -r flags
• history N to show last N entries

Terminal

• Raw mode input (char-by-char via termios)
• Termios restore on exit

Planned

• Glob expansion (*, ?, **)
• Environment variable expansion ($VAR, ${VAR})
• && and || operators
• Job control (&, fg, bg, jobs)
• Signal handling (SIGINT, SIGTSTP)
• Aliases and functions
• Prompt customization