# Processes

Processes can be investigated through a variety of tools:

1. The files in `/proc/$PID/`, in particular
   - `/proc/$PID/fd/*`: the open files of the process
   - `/proc/$PID/environ`: the process' environment
2. `strace` allows tracing a process' system calls.
3. `ltrace` allows tracing a process' library calls.

```{note}
Both `strace` and `ltrace` slow the target process down **a lot**, which might cause problems.
```