Uploading photos from my Canon EOS 20D to Linux
 

I'm trying to upload photos from my Canon EOS 20D. I plugged the USB cord and turn the camera on, but nothing happens. Do I need a special Linux software? The camera didn't bring any cd's inside the box. Please help.

I usually use digikam software to move photos from my camera to my computer. You forgot to indicate which distribution of Linux you use which would be useful information as their is other software available besides digikam and it may not be installed by default. On some distributions when you plug something in to a usb port, it is automatically shown in the /media directory. You might check that.

take the memory card out of it, put the card into a reader and connect the reader to your pc.
or: is there a setup in your camera? exchange bluetooth, exchange HDD, exchange USB..? then choose the correct setup in the camera.

Canon, in their infinite wisdom, decided that USB mass storage wasn't for them so you'll need to either use a card reader as suggested by floppy_stuttgart or install something like digiKam (which, I think, is what I have used in the past with my 450D).

I always take the memory card out and use a card reader, regardless of which digital camera I used for the photos. Haven't connected a camera to my computer in years.