Command: lsof -p processID
Example: lsof -p 4048
More info, source: http://forum.ensim.com/showthread.php?t=18798

/usr/sbin/useradd -g groupname username
more info here

wget
Example: wget http://wilmer.gaast.net/downloads/axel-1.0b.tar.gz

cd /usr/tom
chown -R tom:group *

All of the commands below assume that you are within the same directory that the compressed file is in.
Type ls {enter} to be sure
How to unzip a .tar.gz/.tgz file?
To extract .tar.gz or .tgz files, run the following command in a terminal:
tar -zxvf file.tar.gz (or file.tgz)
This will normally create a new directory based on the [...]