> For the complete documentation index, see [llms.txt](https://documentation.hak5.org/packet-squirrel-mark-ii/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://documentation.hak5.org/packet-squirrel-mark-ii/advanced-payloads/command-groups.md).

# Command groups

Sometimes you'll want to run multiple commands, and take action if *any* of them complete.  For example, the `MATCHSTREAM` command matches streams and ports, but a payload may need to match multiple streams on multiple ports.

## The wait command

Bash includes a built-in command, `wait`, which waits for a backgrounded command to complete.

By default, `wait` will pause until all backgrounded commands are complete, however by using `wait -n`, it will end when *any* backgrounded command completes.

## The pkill command

The `pkill` command simplifies dealing with groups of processes.

While it has many options, we'll be using the `-P` option, which kills all subprocesses of a shell.

Coupled with the Bash variable `$$` which expands to the process ID of the current shell, this lets us automatically kill all background processes of the current group:

```bash
pkill -P $$
```

## Putting it together

Combing `wait -n` and `pkill` allows us to run any number of background commands, and immediately respond if *any* of them finish.

We then use `pkill` to kill the rest of the commands that are still running.

## Example

```bash
#!/bin/bash

# Title: Command group demo
#
# Description: Jail the device instantly if it attempts to do HTTP basic auth or meterpreter

# Bridge mode
NETMODE BRIDGE

# Run the commands as a group
{
    # Run MATCHSTREAM and MATCHPORT in the background
    MATCHSTREAM eth0 TCP 80 'Basic-Auth:' &
    MATCHPORT eth0 ANY 4444 &
    # Wait for any command to complete
    wait -n
    # Kill any remaining commands
    pkill -P $$
}

# If we get to here, MATCHSTREAM or MATCHPORT has completed

# Go into jail mode
NETMODE JAIL
LED R SOLID
```


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://documentation.hak5.org/packet-squirrel-mark-ii/advanced-payloads/command-groups.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.