import sys, shutil, subprocess, os, shlex, msvcrt
builtin_commands = {}
def command(func):
builtin_commands[func.__name__.split("_")[1]] = func
return func
@command
def shell_exit(args):
exit(int(args[0]))
@command
def shell_echo(args):
sys.stdout.write(" ".join(args) + "\n")
@command
def shell_type(args):
if args[0] in builtin_commands:
sys.stdout.write(f"{args[0]} is a shell builtin\n")
elif path := shutil.which(args[0]):
sys.stdout.write(f"{args[0]} is {path}\n")
else:
sys.stderr.write(f"{args[0]}: not found\n")
@command
def shell_pwd(args):
sys.stdout.write(f"{os.getcwd()}\n")
@command
def shell_cd(args):
path = args[0]
if os.path.isdir(path) or path == "~":
os.chdir(os.path.expanduser(path))
else:
sys.stderr.write(f"cd: {path}: No such file or directory\n")
def get_completion(input):
return list(filter(lambda cmnd: cmnd.startswith(input), builtin_commands))
def write_and_flush(data):
sys.stdout.write(data)
sys.stdout.flush()
def get_input():
user_input = ""
print("$ ", end="", flush=True)
while True:
char = msvcrt.getwch()
if char == "\r":
print()
return user_input
elif char == "\b":
if len(user_input) > 0:
user_input = user_input[:-1]
print("\b \b", end="", flush=True)
elif char == "\t":
completions = get_completion(user_input.strip())
if completions:
completion = completions[0]
user_input = completion + " "
sys.stdout.write(f"\r$ {user_input}")
sys.stdout.flush()
else:
user_input += char
print(char, end="", flush=True)
sys.stdout.write("\n")
return user_input
def redirect(args, command, operator):
if len(args) < 3:
return
redirect_index = args.index(operator)
cmd_args = args[:redirect_index]
file_name = args[redirect_index + 1]
method = "w" if operator in [">", "1>", "2>"] else "a"
if command in builtin_commands:
try:
with open(file_name, method) as f:
old_output = sys.stdout if operator in [">", "1>",">>","1>>"] else sys.stderr
if operator in [">", "1>",">>","1>>"]:
sys.stdout = f
elif operator in ["2>", "2>>"]:
sys.stderr = f
builtin_commands[command](cmd_args)
except Exception as e:
sys.stdout.write(f"Error executing command {command}: {e}\n")
finally:
if operator in [">", "1>",">>","1>>"]:
sys.stdout = old_output
elif operator in ["2>", "2>>"]:
sys.stderr = old_output
else:
executable = shutil.which(command)
if executable:
with open(file_name, method) as f:
if operator in [">", "1>",">>","1>>"]:
subprocess.run([command] + cmd_args, stdout=f)
else:
subprocess.run([command] + cmd_args, stderr=f)
else:
sys.stdout.write(f"{command}: command not found\n")
def main():
while True:
user_input = get_input()
cmd, *args = shlex.split(user_input)
redirect_operator = next((operator for operator in [">","1>","2>",">>", "1>>", "2>>"] if operator in args), None)
if redirect_operator:
redirect(args, cmd, redirect_operator)
else:
if cmd in builtin_commands:
builtin_commands[cmd](args)
elif executable := shutil.which(cmd):
subprocess.run([cmd] + args)
else:
sys.stdout.write(f"{cmd}: command not found\n")
if __name__ == "__main__":
main()
Hey @Jebach0, what errors are you seeing?
@andy1li This is the output I’m getting
remote: [tester::#QP2] Running tests for Stage #QP2 (Autocompletion - Builtin completion)
remote: [tester::#QP2] Running ./your_program.sh
remote: [tester::#QP2] ✓ Received prompt ($ )
remote: [tester::#QP2] Typed “ech”
remote: [tester::#QP2] ✓ Prompt line matches “$ ech”
remote: [tester::#QP2] Pressed “” (expecting autocomplete to “echo”)
remote: [your-program] $ ech
remote: [tester::#QP2] Output does not match expected value.
remote: [tester::#QP2] Expected: "$ echo "
remote: [tester::#QP2] Received: "$ ech "
remote: [tester::#QP2] Assertion failed.
remote: [tester::#QP2] Test failed (try setting ‘debug: true’ in your codecrafters.yml to see more details)
remote:
remote: Try our CLI to run tests faster without Git: How do I install the CLI? - CodeCrafters
remote:
remote: View our article on debugging test failures: How do I debug test failures? - CodeCrafters
remote:
To https://git.codecrafters.io/5ac8d4f248023317
@Jebach0 Nice use of the command decorator! 
The default setup does not allow reading one char at a time from stdin:
Input is currently buffered until enter is pressed. To handle character-by-character input, you may want to research raw mode or use readline.
Let me know if you’d like further clarification!
Closing this thread due to inactivity. If you still need assistance, feel free to reopen or start a new discussion!