# Setting PYTHONPATH to include all subdirectories under a parent folder in Linux/Unix
export PYTHONPATH=$(find /home/$USER -type d -printf '%p:')$PYTHONPATH

# For macOS (BSD find)
export PYTHONPATH=$(find -E /home/$USER -type d -exec printf '%s:' {} +)$PYTHONPATH

Managing PYTHONPATH manually becomes tedious when working with multiple projects or nested directory structures. The traditional approach requires explicitly listing each directory:

# Inefficient manual approach
export PYTHONPATH=/path/to/project:/path/to/project/subdir1:/path/to/project/subdir2

For modern Python development workflows, we can dynamically generate PYTHONPATH to include all relevant directories:

# Bash function for your .bashrc or .zshrc
update_pythonpath() {
    local root_dir=${1:-$HOME}
    export PYTHONPATH=$(find "$root_dir" -type d -name "venv" -prune -o -type d -printf '%p:' | sed 's/:$//')
}

For more control over which directories get included:

# Only include directories containing __init__.py (Python packages)
export PYTHONPATH=$(find /home/$USER -type f -name '__init__.py' -printf '%h\n' | sort -u | tr '\n' ':' | sed 's/:$//')

To make this persistent across terminal sessions, add to your shell configuration:

# Add to ~/.bashrc or ~/.zshrc
PYTHONPATH_INCLUDE_ROOT="$HOME/code"  # Customize this
export PYTHONPATH=$(find "$PYTHONPATH_INCLUDE_ROOT" -type d -printf '%p:' | sed 's/:$//'):$PYTHONPATH

Within Python scripts, you can modify sys.path programmatically:

import os
import sys
from pathlib import Path

def add_subdirs_to_path(root_dir):
    root = Path(root_dir)
    for directory in root.rglob('*'):
        if directory.is_dir():
            sys.path.append(str(directory))

add_subdirs_to_path('/home/user/projects')

• Be cautious with recursive directory inclusion - it may add unnecessary paths
• Consider excluding virtual environments (venv, .venv, env)
• For large directory trees, this may impact Python import performance
• In production, prefer explicit paths or proper package installation

When working on large Python projects, manually specifying every directory in PYTHONPATH becomes tedious. Consider this common scenario:

export PYTHONPATH=/projects/core:/projects/core/utils:/projects/core/utils/helpers

This approach doesn't scale well and breaks when new subdirectories are added.

We can create a script to automatically discover and add all subdirectories:

import os
import sys

def add_subdirs_to_path(root_dir):
    for dirpath, dirnames, filenames in os.walk(root_dir):
        if '__init__.py' in filenames:  # Only add Python packages
            sys.path.append(dirpath)

# Usage:
add_subdirs_to_path('/home/user/projects')

For those who prefer shell solutions, here's a Bash function:

update_pythonpath() {
    local root_dir=$1
    export PYTHONPATH=$(find "$root_dir" -type d | tr '\n' ':' | sed 's/:$//')
}

# Usage:
update_pythonpath "/home/$USER/repository"

1. Be cautious with recursive directory inclusion - it might add unwanted paths

2. Consider performance impact when working with deep directory structures

3. Remember that the order of paths matters in Python imports

For enterprise environments, consider this robust implementation:

#!/usr/bin/env python3

import os
import sys
from pathlib import Path

def init_pythonpath(base_path, max_depth=5):
    base = Path(base_path).expanduser().resolve()
    paths = set()
    
    for depth in range(max_depth + 1):
        for dirpath in base.glob('*/' * depth):
            if (dirpath / '__init__.py').exists():
                paths.add(str(dirpath))
    
    sys.path.extend(sorted(paths, key=lambda p: -len(p.split(os.sep))))

if __name__ == '__main__':
    init_pythonpath('~/repository')