unix-shell

A small Unix-like shell written in Go.

This project runs an interactive prompt, executes built-in commands, resolves external programs from PATH, and supports basic shell parsing features such as quoting, escaping, tilde expansion, and output redirection.

What it supports

• Built-ins: exit, echo, pwd, type, cd
• External command execution through PATH
• Single quotes and double quotes
• Backslash escaping
• ~ expansion for the home directory
• Redirection for stdout and stderr:
  • >
  • >>
  • 1>
  • 1>>
  • 2>
  • 2>>

Project layout

app/
  main.go              interactive shell loop
  commands/
    tokens.go          command parsing and redirection detection
    run.go             external command execution
    helpers.go         output helpers for built-ins

Run locally

Requirements:

• Go installed locally

Start the shell:

./run.sh

If you prefer running Go directly:

go run ./app

Example commands

pwd
echo hello world
type echo
cd /tmp
ls
echo "hello" > out.txt
cat missing.txt 2> errors.txt
echo again >> out.txt

Notes

• Built-in output redirection is handled inside the shell.
• External commands inherit the current terminal unless redirected.
• On Windows/MSYS environments, append redirection is handled explicitly for better compatibility with child processes.