whichcraft

Common errors

• which('my_command') returns None on Windows when I expect a path, but works on Linux.

  cause The command you are searching for (`my_command`) might be an internal shell command (e.g., `date`, `dir`) on Windows, not a standalone executable file that exists on the system's PATH. `whichcraft.which` primarily finds external executable files.
  fix Verify if `my_command` is an actual executable file (`.exe`, `.bat`, `.cmd`) on Windows and if its directory is included in the system's PATH environment variable. If it's a shell built-in, `whichcraft` cannot locate it. For such commands, consider using `subprocess` with `shell=True` (with caution) or Python's native functionalities.

• ImportError: cannot import name 'which' from 'whichcraft' (or similar import errors)

  cause This typically means the `whichcraft` package is either not installed, or there's a typo in the import statement, or there's a naming conflict with another module or file named `whichcraft.py` in your project's directory or Python path.
  fix First, ensure the library is installed: `pip install whichcraft`. Second, double-check the import statement: `from whichcraft import which`. Third, if you have a file named `whichcraft.py` in your current working directory or a directory on your `PYTHONPATH`, Python might be trying to import from your local file instead of the installed package. Rename your local file or ensure it's not shadowing the package.

Warnings

• gotcha The behavior of `whichcraft.which('date')` (or similar internal system commands) differs between Windows and Unix-like systems. On Unix-like systems (Linux, macOS), `date` is typically a standalone executable returning its path. On Windows, `date` is often an internal shell command (cmd.exe built-in) and thus `whichcraft.which` will return `None`, as it only searches for external executables on the PATH.
  Fix: When using `whichcraft.which` for common system commands, be aware of OS-specific differences. For commands that are shell built-ins on some platforms, `which` will return `None`. Consider using platform-agnostic Python equivalents (e.g., `datetime` module for dates) or OS-specific checks if relying on such commands.
• deprecated For Python 3.3 and newer, the functionality provided by `whichcraft` is natively available in the standard library as `shutil.which`. While `whichcraft` still works, it may not be necessary for projects targeting only modern Python 3 versions, as its primary value was cross-version (Python 2.7 and Python 3.x) compatibility and Windows support for older Python 3 versions.
  Fix: For new projects or existing projects targeting Python 3.3+, consider using `from shutil import which` directly. Only use `whichcraft` if you need Python 2.7 compatibility or require its specific cross-platform shim for certain edge cases.

Install

• pip install whichcraft Install stable release

Imports

• which

  from whichcraft import which

Quickstart

This quickstart demonstrates how to import the `which` function and use it to find the path to various executables. It shows successful discovery, a non-existent command returning `None`, and highlights the cross-platform behavior for common commands like 'date'.

from whichcraft import which

# Find the path to a common executable
python_path = which('python')
print(f"Python executable found at: {python_path}")

# Try to find a command that might not exist
non_existent_command = which('nonexistent_command_123')
print(f"Non-existent command found at: {non_existent_command}")

# Example of a command that might behave differently across OS (e.g., 'date')
date_command = which('date')
print(f"'date' command found at: {date_command}")