nosh

Nosh stands for no shell. It provides pure Python functions for file manipulation (moving, copying, deleting etc.) and other shell-like tasks such as directory listing and archive management, with a consistent API.

Nosh implements Python functions inspired by common shell commands such as mv, ls, cp etc. It does not try to strictly copy their functionality and arguments, but to follow their semantics, and to expose a clearer API than Python's builtin libraries. Nosh also provides extra helper functions, such as a context manager for switching directories within a block.

Since nosh uses only Python's own builtin functions internally, it should work on any platform supported by Python (as opposed to tools like the sh module that directly call the real commands).

Philosophy

I created nosh after becoming frustrated with the file management functions of Python's standard library, spread across os, os.path, shutil and other modules. This API is inconsistent and inconvenient - for instance, the actions you'd accomplish with the cp shell command are spread across shutil.copy, shutil.copy2, shutil.copyfile, shutil.copytree and several others! These do not all have the same semantics, e.g. shutil.copy can copy a file to inside a target folder, while shutil.copytree requires that the target folder does not already exist. There may be good reasons for these distinctions, but it doesn't make for simple code.

nosh's functions are inspired by the shell equivalents, but are simple alternatives that do not try to fully implement them. For instance, instead of having to check if a file is a directory etc. before deciding what copy function to use, you can use code like the following:

# shell command (`target` is a directory)
cp *.txt example.mp3 some_folder_name target

# nosh
import nosh
nosh.cp('*.txt', 'example.mp3', 'some_folder_name', 'target', recursive=True)

# Python stdlib
import glob
import shutil
from os.path import join
filens = glob.glob('*.txt') + ['example.mp3']
for filen in filens:
    shutil.copy(filen, 'target')
shutil.copytree('some_folder_name', join('target', 'some_folder_name'))

Examples

Here are some examples of basic nosh functionality:

import nosh as no

# Create some files and directories
for i in range(5):
no.touch('{}.txt'.format(i))  # no.touch creates the files
no.mkdir('dir1')
no.mkdir('dir2/dir2_contents', parents=True)
    # when parents=True, both dirs are created
    # if parents=False, this would raise an error
no.mkdir('dir3')

print(no.ls())  # ['1.txt', '4.txt', '3.txt', '2.txt', '0.txt', 'dir2', 'dir1']

# Copy files around
no.cp('1.txt', '1_copy.txt')
print(no.ls())  # ['1.txt', '4.txt', '3.txt', '1_copy.txt', '2.txt', '0.txt', 'dir2', 'dir1']

no.cp('[1-3].txt', 'dir1')  # glob patterns are supported
print(no.ls('dir1'))  # ['1.txt', '3.txt', '2.txt']

no.cp('dir2', 'dir1', recursive=True) # Directories can be copied the same way
print(no.ls('dir1'))  # ['1.txt', '3.txt', '2.txt', 'dir2']
print(no.ls('dir1/dir2'))  # ['dir2_contents']

# Move files
print(no.ls())  # ['1.txt', '4.txt', '3.txt', '1_copy.txt', '2.txt', '0.txt', 'dir2', 'dir1']
print(no.ls('dir3'))  # []

no.mv('1.txt', 'dir3')
print(no.ls())  # ['4.txt', '3.txt', '1_copy.txt', '2.txt', 'dir3', '0.txt', 'dir2', 'dir1']
print(no.ls('dir3'))  # ['1.txt']

no.mv('2.txt', 'dir3/moved_2.txt')  # Moving files can rename them
print(no.ls())  # ['4.txt', '3.txt', '1_copy.txt', 'dir3', '0.txt', 'dir2', 'dir1']
print(no.ls('dir3'))  # ['1.txt', 'moved_2.txt']

# Delete files
no.rm('1_copy.txt')
print(no.ls())  # ['4.txt', '3.txt', 'dir3', '0.txt', 'dir2', 'dir1']

no.rm('dir3', recursive=True)  # Can also delete directories
print(no.ls())  # ['4.txt', '3.txt', '0.txt', 'dir2', 'dir1']

no.rm('*.txt')  # Glob patterns can be used here too
                # (and in most other commands)
print(no.ls())  # ['dir2', 'dir1']

no.rm('*', recursive=True)  # Clean all the directories
print(no.ls())  # []

Other features

Fail on unexpected behaviour

Unlike the shell, nosh tries to raise errors rather than continuing processing when e.g. you try to copy a directory without recursive=True (whereas cp would just print cp: omitting directory 'dirname'). You can tell individual commands to ignore such problems for more shell-like behaviour by passing ignore_errors=True.

# in bash
mkdir testdir
cp testdir testdir2  # prints 'cp: omitting directory 'testdir''
cp -r testdir testdir2  # works

# in Python with nosh
import nosh as no
no.mkdir('testdir')
no.cp('testdir', 'testdir2')  # raises IsADirectoryError
no.cp('testdir', 'testdir2', recursive=True)  # works
no.cp('testdir', 'testdir2', ignore_errors=True) 
    # prints 'Error: Tried to copy directory but recursive is False.'
    # but does not raise an exception and would process other args

Directory convenience utilities

nosh provides some utilities for working with directories.

Temporarily moving into a directory:

from nosh import current_directory, pwd
with current_directory('some_dir_name'):
    # within this block, we are in `some_dir_name`
    print(pwd())  # will print /path/to/some_dir_name

Creating a temporary directory that is removed outside the context:

from nosh import temp_directory
from os.path import exists
with temp_directory() as temp_dir:
    print(temp_dir)  # will print something like /tmp/tmpsg_kdx64
    print(exists(temp_dir))  # True
print(exists(temp_dir))  # False