minishell

An idiot admires complexity, a genius admires simplicity

©️ Legend Terry A. Davis

I want to ditch Bash and replace all use cases of it with Python. I recently learned that there's no good alternative for Bash. You can argue that there is, but then compare what they can write in Bash and how unreadable it becomes with any of the traditional shell solutions out there.

Goals

• minishell is going to be extremely simple
• Compete with Bash only
• Do not add features just because other libraries have them
• Stay focused: execute commands and parse arguments, nothing more

Philosophy

Bash works because it's the shell. You can't replicate that. But you can make Python script writing as painless as Bash for everything else: better error handling, better argument parsing, better readability.

minishell provides just what you need:

• shell(cmd, *args) - Run commands with full TTY support and optional argument escaping
• shell[cmd, *args] - Same as previous, but capture output
• shell.args[1], shell.args.named_argument - Parse CLI arguments automatically

That's it. No frameworks, no magic.

Quick Start

# Raw command
shell("ls -la | grep test")

# With escaped arguments (safe!)
filename = "file with spaces.txt"
shell("rm {}", filename)

# Capture output
result = shell["pwd"]
print("Current dir:", result.output)

# Arguments are auto-parsed
app_name = shell.args.app_name
if not app_name:
    shell.exit("Error: --app-name required")

API

shell(cmd, *args, exit_on_error=True)

Execute a command with optional argument escaping.

• cmd: Command string with optional {} placeholders
• args: Arguments to format and escape
• exit_on_error: Exit on non-zero exit code (default: True)

shell("echo hello")                      # raw
shell("echo {}", "hello")                # with escaping
shell("ls", exit_on_error=False)         # don't exit on error

shell[cmd, *args]

Execute command and capture output.

result = shell["pwd"]
print(result)

shell.args

Automatically parsed command-line arguments.

# Positional
print(shell.args[0])

# Named arguments
print(shell.args.config)
print(shell.args.verbose)

# Multiple values become lists
if isinstance(shell.args.file, list):
    for f in shell.args.file:
        print(f)

shell.temp()

Context manager for temporary files.

with shell.temp() as tmp:
    shell(f"command > {tmp}")
    result = tmp.read()
    # file auto-deleted on exit

Installation

pip install minishell

Or just copy minishell.py to your project.

Why not Bash?

Feature	Bash	minishell
Argument parsing	50+ lines	3 lines
Variable syntax	$VAR, ${VAR}	f-strings
Error handling	set -e (fragile)	Explicit
Type hints	None	Full typing
Readability	Medium	High

Contributing

We need Bash specialists to provide code examples that are:

• Cleaner/simpler in Bash than in Python with minishell
• Real-world use cases we should optimize for

Alternatively, suggest improvements to keep the library minimal and focused. Pure critique without suggestions is also appreciated!

The bar for adding features: Does this save significant boilerplate compared to Bash?