# import os

**[import os](https://docs.python.org/3/library/os.html)** is a Python import that provides functions for interacting with the operating system: file paths, environment variables, process information, and filesystem operations. Use this for cross-platform file handling, reading environment, and running system commands.

## Example

```python
# Python
# description: list files in current directory, get home path

import os

# Print current working directory
print(os.getcwd())

# List files in directory
for name in os.listdir('.'):
    print(name)

# Access environment variables
home = os.environ.get('HOME')
print(f"Home: {home}")

# Get process ID
print(f"Process ID: {os.getpid()}")
```

## Common functions

- `os.getcwd()`: current working directory
- `os.chdir(path)`: change directory
- `os.listdir(path)`: list directory contents
- `os.makedirs(path)`: create directories
- `os.remove(path)`: delete a file
- `os.rmdir(path)`: delete an empty directory
- `os.rename(src, dst)`: rename file
- `os.path.exists(path)`: check if path exists
- `os.path.join(...)`: join path components (use `pathlib` for modern code)
- `os.environ`: environment variables dictionary
- `os.getenv(key, default)`: get environment variable
- `os.getpid()`: current process ID
- `os.walk(path)`: walk directory tree recursively