# os.chdir

The `os.chdir` function changes the execution directory for subsequent operations in the current script. It does not change the host Atmos process directory or other script invocations.

## Usage

```python
os.chdir(path)
```

## Arguments

- **`path`**
  Required. A nonempty string naming an existing directory, without null bytes. Relative paths resolve against the script's current directory; a leading 
  `~`
   expands as it does for 
  `fs.*`
  .

Returns `None`. Missing paths and paths that are not directories raise an error and leave the current directory unchanged.
After a successful change, `os.getcwd()`, relative `fs.*` operations, `exec.which`, and the default directories for
`exec.run`, `atmos.*`, and `steps.*` use the new directory. An explicit per-call `working_directory=` takes precedence.
`component.exec` continues to default to its component's directory. File-backed `load()` imports remain relative to
the importing file; inline scripts resolve imports against their current execution directory.

Before any `os.chdir` call, `atmos.*` retains its usual default of the directory Atmos was invoked from.
Calling `os.chdir` explicitly changes that default as well as the script directory.

Call this function only in the script's main thread. Parallel tasks inherit the directory already selected by their parent;
calling `os.chdir` inside a parallel task raises an error, even with `max_concurrency=1`.
Use per-call `working_directory=` for different directories in different branches.

## Examples

```python
original = os.getcwd()
os.chdir("generated")
fs.write_file("settings.json", json.encode({"enabled": True}))
exec.run(["my-tool", "validate"])
os.chdir(original)
```

## Related

- [`os.getcwd`](/functions/automation/os.getcwd) reads the script's current directory.
- [`fs.resolve`](/functions/automation/fs.resolve) resolves relative paths without changing the directory.