How many GBs left?

I have a SanDisk Cruzer Glide 64 GB flashdrive.

I have an IMac computer, OSX Mountain Lion,  and ITunes.

I dragged all my ITunes song files (several thousand)  to the flashdrive in order to have them backed up.  I have 2 questions:

  1. How do I know how many GBs have been used up on my flash drive, or how many GBs are left?

  2. I know many of my ITunes song files were duplicates, even a few triplicates. Is there a way to remove the duplicate song files from my flashdrive, in order to save space? (There is no need to have the same song file in my flashdrive 2 or 3 times.). 

http://forums.sandisk.com/t5/All-SanDisk-USB-Flash-Drives/Did-I-transfer-all-my-files/m-p/294232/highlight/true#M4946

I would think this question is more about the flashdrive than ITunes. I am trying to find out how many GBs I have left in my flashdrive. Also, how to get rid of duplicate music files in my flashdrive. 

@henryr wrote:

I would think this question is more about the flashdrive than ITunes. I am trying to find out how many GBs I have left in my flashdrive. Also, how to get rid of duplicate music files in my flashdrive. 

No, it’s not. The flash drive is not going to tell you the amount of available space it has, only the computer you plug it into can do that.

There are also special programs written exclusively for Macs that address the subject of multiple files. Again, not a flash drive issue. One though that could be Googled or asked about (and most likely answered) on Mac, or Apple-specific forums.

1) How do I know how many GBs have been used up on my flash drive, or how many GBs are left?”

I am trying to find out how many GBs I have left in my flashdrive.”

Plug it into a Windows machine, open Windows Explorer, RIGHT click on the drive name, click on Properties.  Free space, Used space, Capacity, etc, etc.  I’m surprised iMacs don’t have a way to show this information.

I put this question on the IMac forum. They said to click on the flashdrive icon on the desktop and then hit COMMAND plus I.

It will then show the disk space used up. They also said that the flashdrive cannot have duplicate files, although I did see a number of dupiicate song files in my flashdrive.

Windows OS also does not allow identically named (or duplicate) files. To prevent this, it will append the file name with (1), (2), (3), etc, so all copies are named slightly different.