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# commands
# `prefect_shell.commands`
Tasks for interacting with shell commands
## Functions
### `shell_run_command`
```python theme={null}
shell_run_command(command: str, env: dict[str, str] | None = None, helper_command: str | None = None, shell: str | None = None, extension: str | None = None, return_all: bool = False, stream_level: int = logging.INFO, cwd: str | bytes | os.PathLike[str] | None = None) -> list[str] | str
```
Runs arbitrary shell commands.
**Args:**
* `command`: Shell command to be executed; can also be
provided post-initialization by calling this task instance.
* `env`: Dictionary of environment variables to use for
the subprocess; can also be provided at runtime.
* `helper_command`: String representing a shell command, which
will be executed prior to the `command` in the same process.
Can be used to change directories, define helper functions, etc.
for different commands in a flow.
* `shell`: Shell to run the command with.
* `extension`: File extension to be appended to the command to be executed.
* `return_all`: Whether this task should return all lines of stdout as a list,
or just the last line as a string.
* `stream_level`: The logging level of the stream;
defaults to 20 equivalent to `logging.INFO`.
* `cwd`: The working directory context the command will be executed within
**Returns:**
* If return all, returns all lines as a list; else the last line as a string.
## Classes
### `ShellProcess`
A class representing a shell process.
Supports both async (anyio.abc.Process) and sync (subprocess.Popen) processes.
**Methods:**
#### `afetch_result`
```python theme={null}
afetch_result(self) -> list[str]
```
Retrieve the output of the shell operation (async version).
**Returns:**
* The lines output from the shell operation as a list.
#### `await_for_completion`
```python theme={null}
await_for_completion(self) -> None
```
Wait for the shell command to complete after a process is triggered (async version).
#### `fetch_result`
```python theme={null}
fetch_result(self) -> list[str]
```
Retrieve the output of the shell operation (sync version).
**Returns:**
* The lines output from the shell operation as a list.
#### `pid`
```python theme={null}
pid(self) -> int
```
The PID of the process.
**Returns:**
* The PID of the process.
#### `return_code`
```python theme={null}
return_code(self) -> int | None
```
The return code of the process.
**Returns:**
* The return code of the process, or `None` if the process is still running.
#### `wait_for_completion`
```python theme={null}
wait_for_completion(self) -> None
```
Wait for the shell command to complete after a process is triggered (sync version).
### `ShellOperation`
A block representing a shell operation, containing multiple commands.
For long-lasting operations, use the trigger method and utilize the block as a
context manager for automatic closure of processes when context is exited.
If not, manually call the close method to close processes.
For short-lasting operations, use the run method. Context is automatically managed
with this method.
**Attributes:**
* `commands`: A list of commands to execute sequentially.
* `stream_output`: Whether to stream output.
* `env`: A dictionary of environment variables to set for the shell operation.
* `working_dir`: The working directory context the commands
will be executed within.
* `shell`: The shell to use to execute the commands.
* `extension`: The extension to use for the temporary file.
if unset defaults to `.ps1` on Windows and `.sh` on other platforms.
**Examples:**
Load a configured block:
```python theme={null}
from prefect_shell import ShellOperation
shell_operation = ShellOperation.load("BLOCK_NAME")
```
**Methods:**
#### `aclose`
```python theme={null}
aclose(self)
```
Close the job block (async version).
#### `arun`
```python theme={null}
arun(self, **open_kwargs: dict[str, Any]) -> list[str]
```
Runs a shell command (async version), but unlike the trigger method,
additionally waits and fetches the result directly, automatically managing
the context. This method is ideal for short-lasting shell commands;
for long-lasting shell commands, it is
recommended to use the `trigger` method instead.
**Args:**
* `**open_kwargs`: Additional keyword arguments to pass to `open_process`.
**Returns:**
* The lines output from the shell command as a list.
**Examples:**
Sleep for 5 seconds and then print "Hello, world!":
```python theme={null}
from prefect_shell import ShellOperation
shell_output = await ShellOperation(
commands=["sleep 5", "echo 'Hello, world!'"]
).arun()
```
#### `atrigger`
```python theme={null}
atrigger(self, **open_kwargs: dict[str, Any]) -> ShellProcess
```
Triggers a shell command and returns the shell command run object
to track the execution of the run (async version). This method is ideal
for long-lasting shell commands; for short-lasting shell commands, it is
recommended to use the `run` method instead.
**Args:**
* `**open_kwargs`: Additional keyword arguments to pass to `open_process`.
**Returns:**
* A `ShellProcess` object.
**Examples:**
Sleep for 5 seconds and then print "Hello, world!":
```python theme={null}
from prefect_shell import ShellOperation
async with ShellOperation(
commands=["sleep 5", "echo 'Hello, world!'"],
) as shell_operation:
shell_process = await shell_operation.atrigger()
await shell_process.await_for_completion()
shell_output = await shell_process.afetch_result()
```
#### `close`
```python theme={null}
close(self)
```
Close the job block (sync version).
#### `run`
```python theme={null}
run(self, **open_kwargs: dict[str, Any]) -> list[str]
```
Runs a shell command (sync version), but unlike the trigger method,
additionally waits and fetches the result directly, automatically managing
the context. This method is ideal for short-lasting shell commands;
for long-lasting shell commands, it is
recommended to use the `trigger` method instead.
**Args:**
* `**open_kwargs`: Additional keyword arguments to pass to subprocess.Popen.
**Returns:**
* The lines output from the shell command as a list.
**Examples:**
Sleep for 5 seconds and then print "Hello, world!":
```python theme={null}
from prefect_shell import ShellOperation
shell_output = ShellOperation(
commands=["sleep 5", "echo 'Hello, world!'"]
).run()
```
#### `trigger`
```python theme={null}
trigger(self, **open_kwargs: dict[str, Any]) -> ShellProcess
```
Triggers a shell command and returns the shell command run object
to track the execution of the run (sync version). This method is ideal
for long-lasting shell commands; for short-lasting shell commands, it is
recommended to use the `run` method instead.
**Args:**
* `**open_kwargs`: Additional keyword arguments to pass to subprocess.Popen.
**Returns:**
* A `ShellProcess` object.
**Examples:**
Sleep for 5 seconds and then print "Hello, world!":
```python theme={null}
from prefect_shell import ShellOperation
with ShellOperation(
commands=["sleep 5", "echo 'Hello, world!'"],
) as shell_operation:
shell_process = shell_operation.trigger()
shell_process.wait_for_completion()
shell_output = shell_process.fetch_result()
```
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