need help transfering files from mac to n7

You could use something like Airdroid, which will allow you to use any browser on your PC no matter what OS you use.

Ubuntu should see any MTP device automatically and allow you to browse it pretty much like any other file system using Nautilus or whatever file manager you use. It "just works" on my Ubuntu-based system.

 

I don't Ubuntu but I do run Linux. MTP works just like a drive.

++1 for Airdroid that is the best way to go really. No wires necessary.

 

This may help you using ES File Explorer which is in my opinion simply the best Android file manager -

[How To] Share files between OS X 10.7+ and Android over WiFi without SAMBA - Internet(s), Servers, and Networks - InsanelyMac Forum

You should also have no problem setting your tablet to USB debug and rooting it from your mac as the entire android dev kit is available for OSX, there are many guides available via google and youtube.

Once rooted you can use a OTG cable and an app called Stick Mount to share files using a USB stick.

 

I have Android File Transfer installed on my MacBook Pro and use it to transfer files to/from the MacBook Pro to the Nexus 7. This is done from the Mac side using drag and drop.

 

Which version of Ubuntu are you using?