# Signals
**Signals** are a way to interact with processes in linux.

Each signal has one of five default actions a process will take when it receives the signal. These can be:
* **Term** -> Terminate the running process.
* **Ign** -> Ignore the signal.
* **Core** -> Terminate the process and dump core.
* **Stop** -> Stop the process.
* **Cont** -> Continue process if stopped.

These are called *dispositions*. It’s what a process does when it receives a signal and, for some signals, they can be changed (with the signal syscall)
Some signals cannot be ignored (they can’t have their disposition changed), like __… which signals??__

You can send all kind of signals with kill! It’s really useful for terminating processes, debugging and just messing with weird signals.

Some really useful signals:

| Signal  | Value | Action    | Comment   |
|---------|-------|-----------|-----------|
| SIGTERM | 15    | Does this | Does that |
| SIGKILL |       |           |           |
|         |       |           |           |
|         |       |           |           |

__NOTE:__ Signal numbering on different architectures Many signals have different numeric values on different architectures (MIPS, for example). Consult the [manpage](https://man7.org/linux/man-pages/man7/signal.7.html) on a full list.



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Complete with info from [manpage](https://man7.org/linux/man-pages/man7/signal.7.html) and bite size linux.