> ## Documentation Index
> Fetch the complete documentation index at: https://docs.servflow.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Command

> Execute shell commands and scripts from your ServFlow workflows

The command action allows you to execute shell commands and scripts directly from your workflows. This is useful for system automation, running scripts, processing files, or integrating with command-line tools.

<Warning>
  Be cautious when using user input in commands. Always validate and sanitize inputs to prevent command injection attacks.
</Warning>

***

## command

Executes shell commands and returns their output.

### Command

The shell command to execute.

|              |           |
| ------------ | --------- |
| **YAML Key** | `command` |
| **Type**     | string    |
| **Required** | Yes       |

The command is executed in the system's default shell. You can use pipes, redirects, and other shell features.

***

## Examples

### Basic Command

List files in a directory:

```docs/actions/command.mdx theme={null}
actions:
  list_files:
    type: command
    config:
      command: "ls -la /data"
    next: response.success
    fail: response.error
```

### Run a Script

Execute a script file:

```docs/actions/command.mdx theme={null}
actions:
  run_backup:
    type: command
    config:
      command: "/scripts/backup.sh"
    next: response.success
    fail: response.backup_failed
```

### Command with Dynamic Values

Use workflow data in commands (with caution):

```docs/actions/command.mdx theme={null}
actions:
  process_file:
    type: command
    config:
      command: "python /scripts/process.py --file {{ .uploaded_file.path }}"
    next: action.store_result
    fail: response.processing_error
```

### Chained Commands

Use pipes and shell operators:

```docs/actions/command.mdx theme={null}
actions:
  search_logs:
    type: command
    config:
      command: "cat /var/log/app.log | grep ERROR | tail -20"
    next: response.errors
```

### Process Command Output

Use the command output in subsequent actions:

```docs/actions/command.mdx theme={null}
actions:
  get_disk_usage:
    type: command
    config:
      command: "df -h / | tail -1 | awk '{print $5}'"
    next: action.check_threshold

  check_threshold:
    type: javascript
    config:
      script: |
        function servflowRun(vars) {
          const usage = parseInt(vars.get_disk_usage.replace('%', ''));
          return {
            usage: usage,
            alert: usage > 80
          };
        }
    next: conditional.should_alert
```

### Environment Variables

Access environment variables in commands:

```docs/actions/command.mdx theme={null}
actions:
  deploy:
    type: command
    config:
      command: "AWS_PROFILE=production /scripts/deploy.sh {{ param \"version\" }}"
    next: response.deployed
    fail: response.deploy_failed
```

***

## Security Considerations

<Note>
  **Never directly interpolate user input into commands.** This can lead to command injection vulnerabilities.
</Note>

### Unsafe Pattern

```docs/actions/command.mdx theme={null}
# DON'T DO THIS - vulnerable to injection
actions:
  unsafe_command:
    type: command
    config:
      command: "echo {{ param \"user_input\" }}"
```

### Safer Pattern

Validate and sanitize input before use:

```docs/actions/command.mdx theme={null}
actions:
  validate_input:
    type: javascript
    config:
      script: |
        function servflowRun(vars) {
          const input = vars.request_filename || '';
          // Only allow alphanumeric characters and underscores
          const sanitized = input.replace(/[^a-zA-Z0-9_]/g, '');
          return sanitized;
        }
    next: action.safe_command

  safe_command:
    type: command
    config:
      command: "cat /data/{{ .validate_input }}.txt"
    next: response.content
```

***

## Common Use Cases

| Use Case             | Example Command                                        |
| -------------------- | ------------------------------------------------------ |
| File operations      | `cp`, `mv`, `rm`, `mkdir`                              |
| Data processing      | `awk`, `sed`, `grep`, `jq`                             |
| System information   | `df`, `free`, `uptime`                                 |
| Running scripts      | `python script.py`, `node script.js`, `bash script.sh` |
| Git operations       | `git pull`, `git log`                                  |
| Container management | `docker ps`, `docker exec`                             |

***

## Next Steps

<CardGroup cols={2}>
  <Card title="Memory" icon="brain" href="/concepts/actions/memory">
    Cache command results for reuse.
  </Card>

  <Card title="Transformation" icon="wand-magic-sparkles" href="/concepts/actions/transformation">
    Process command output with JavaScript.
  </Card>

  <Card title="Flow Control" icon="code-branch" href="/concepts/actions/flow-control">
    Run multiple commands in parallel.
  </Card>

  <Card title="Actions Overview" icon="play" href="/concepts/actions/overview">
    Learn the fundamentals of ServFlow actions.
  </Card>
</CardGroup>