<p>When you run <code>top</code> and see all running processes, I've always wanted to know just what everything actually means.  e.g. all the various single-letter state codes for a running process (R = Running, S = Sleeping, etc...)</p>
<p>Where can I find this?</p>

You can use the command
```
man top
```
to look up the states:
```
```
D = uninterruptible sleep
I = idle
R = running
S = sleeping
T = stopped by job control signal
t = stopped by debugger during trace
Z = zombie
```
```