You may see a process running and wonder exactly where it's running from. Fortunately, there's a way to find out!

Let's say, for instance, the process is as follows:

# ps aux | grep perl | tail -1
user 852679  0.0  0.0  30920  2472 ?        S    Feb17   0:00 perl main.css

To find out where 'perl main.css' started from:

# ls -l /proc/852679/cwd
lrwxrwxrwx 1 user user 0 Feb 22 16:16 /proc/852679/cwd -> /home/user/public_html/domain.com/

As you can see, process 852679 originated from the directory /home/user/public_html/domain.com/

This can be helpful when tracking down processes that you've not seen before, malware, etc.