How can I tell if something is being downloaded or not using terminal?

How can I tell if something is being downloaded or not using terminal? Like in windows task manager.

You can search your App Menu (Just open the app menu and start typing your search) for “System Monitor.” It is a powerful TaskManager-like utility.

To check network activity in terminal, run

lsof -i

I just typed it in and got this, what do you make of this?

~$ lsof -1
lsof: illegal option character: 1
lsof 4.89
latest revision: ftp://lsof.itap.purdue.edu/pub/tools/unix/lsof/
latest FAQ: ftp://lsof.itap.purdue.edu/pub/tools/unix/lsof/FAQ
latest man page: ftp://lsof.itap.purdue.edu/pub/tools/unix/lsof/lsof_man
usage: [-?abhKlnNoOPRtUvVX] [+|-c c] [+|-d s] [+D D] [+|-E] [+|-e s] [+|-f[gG]]
[-F [f]] [-g [s]] [-i [i]] [+|-L [l]] [+m [m]] [+|-M] [-o [o]] [-p s]
[+|-r [t]] [-s [p:s]] [-S [t]] [-T [t]] [-u s] [+|-w] [-x [fl]] [–] [names]
Use the ``-h’’ option to get more help information.

It is

lsof -i

Not -1. The letter “i”.

I think this, along with double dashes appearing as one long dash in the forum font may be grounds for improvement of the forums display. I think I will cite this thread in that suggestion box.
The forum font needs to be more legible.