shpyx 0.0.18

Simple, clean and modern library for executing shell commands in Python

shpyx is a simple, clean and modern library for executing shell commands in Python.

Use shpyx.run to run a shell command in a subprocess:

>>> import shpyx
>>> shpyx.run("echo 1").return_code
0
>>> shpyx.run("echo 1").stdout
'1\n'
>>> shpyx.run("echo 1").stderr
''
>>> shpyx.run("echo 1")
ShellCmdResult(cmd='echo 1', stdout='1\n', stderr='', all_output='1\n', return_code=0)

Installation

Install with pip:

pip install shpyx

Usage examples

Run a command:

>>> import shpyx
>>> shpyx.run("echo 'Hello world'")
ShellCmdResult(cmd="echo 'Hello world'", stdout='Hello world\n', stderr='', all_output='Hello world\n', return_code=0)

Run a command and print live output:

>>> shpyx.run("echo 'Hello world'", log_output=True)
Hello world
ShellCmdResult(cmd="echo 'Hello world'", stdout='Hello world\n', stderr='', all_output='Hello world\n', return_code=0)

Motivation

I've been writing automation scripts for many years, mostly in Bash.

I love Bash scripts, but in my opinion they become extremely hard to read, maintain and reason about once they grow too big. I find Python to be a much more pleasant tool for "gluing" together pieces of a project and external Bash commands.

Here are things that one might find nicer to do in Python than in bare Bash:

1. String/list manipulation
2. Error handling
3. Flow control (loops and conditions)
4. Output manipulation

The Python standard library provides the excellent subprocess module , which can be used to run bash commands through Python:

import subprocess

cmd = "ls -l"
p = subprocess.Popen([cmd], shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
cmd_stdout, cmd_stderr = p.communicate()

It's great for a very simple, single command, but becomes a bit tedious to use in more complex scenarios, when one or more of the following is needed:

• Run many commands
• Inspect the return code
• See live command output (while it is being run)
• Gracefully handle commands that are stuck (due to blocking I/O, for example)
• Add formatted printing of every executed command and/or its output

This often leads to each project having their own "run" function, which encapsulates subprocess.Popen.

This library aims to provide a simple, typed and configurable run function, dealing with all the caveats of using subprocess.Popen.

Security

Essentially, shpyx is a wrapper around subprocess.Popen. The call to subprocess.Popen uses shell=True which means that an actual system shell is being created, and the subprocess has the permissions of the main Python process.

It is therefore not recommended running untrusted commands via shpyX.

For more info, see security considerations.