The which Command in Python

1. Use the shutil.which() Function to Emulate the which Command in Python
2. Create a Function to Emulate the which Command in Python

In Linux, we have the which command. This command can identify the path for a given executable.

In this tutorial, we will emulate this command in Python.

Use the shutil.which() Function to Emulate the which Command in Python

We can emulate this command in Python using the shutil.which() function. This function is a recent addition in Python 3.3. The shutil module offers several functions to deal with the operations on files and to their collections.

The shutil.which() function returns the path of a given executable, which would run if cmd was called.

For example,

import shutil

print(shutil.which("python"))

Output:

C:\Anaconda\python.EXE

In the above example, the shutil.which() returns the directory of the Python executable.

Create a Function to Emulate the which Command in Python

Below Python 3.3, there is no way to use the shutil.which() function. So here, we can create a function using functions from the os module (os.path.exists()) and os.access methods) to search for the given executable and emulate the which command.

See the following code.

import os


def which(pgm):
    path = os.getenv("PATH")
    for p in path.split(os.path.pathsep):
        p = os.path.join(p, pgm)
        if os.path.exists(p) and os.access(p, os.X_OK):
            return p


print(which("python.exe"))

Output:

C:\Anaconda\python.exe