shell starter

shell.py

#!/usr/bin/env python3

import os

while True:
    line = input('> ')
    os.execvp(line, [line])

# 0. run this code and try `ls` to make sure that much works
# 1. handle arguments (`ls /`)
# 2. don't exit after a command runs (use os.fork and .wait)
# 3. I/O redirection (`echo hi > out`; use os.dup2)
# 4. builtins (`cd`, `pwd` for now)
# 5. forward signals (just SIGINT for now, use signal)
# 6. pipes (`ls | sort`; use os.pipe)
# 7. job control part 1: handle commands ending in `&`
# 8. job control part 2: Ctrl+Z == SIGSTOP, `jobs`, `fg`, `bg`

# see also:
# http://doc.cat-v.org/unix/pipes/
# https://www.raylu.net/systems/