Skip to main content
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.
Be cautious when using user input in commands. Always validate and sanitize inputs to prevent command injection attacks.

​
command

Executes shell commands and returns their output.

​
Command

The shell command to execute.
YAML Keycommand
Typestring
RequiredYes
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: 
actions:
  list_files:
    type: command
    config:
      command: "ls -la /data"
    next: response.success
    fail: response.error

​
Run a Script

Execute a script file: 
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): 
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: 
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: 
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: 
actions:
  deploy:
    type: command
    config:
      command: "AWS_PROFILE=production /scripts/deploy.sh {{ param \"version\" }}"
    next: response.deployed
    fail: response.deploy_failed

​
Security Considerations

Never directly interpolate user input into commands. This can lead to command injection vulnerabilities.

​
Unsafe Pattern

# 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: 
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 CaseExample Command
File operationscp, mv, rm, mkdir
Data processingawk, sed, grep, jq
System informationdf, free, uptime
Running scriptspython script.py, node script.js, bash script.sh
Git operationsgit pull, git log
Container managementdocker ps, docker exec

​
Next Steps

Memory

Cache command results for reuse.

Transformation

Process command output with JavaScript.

Flow Control

Run multiple commands in parallel.

Actions Overview

Learn the fundamentals of ServFlow actions.