I dealt with this issue and found out that at the moment Unity3d is not coming on Linux.
I'm using Ubuntu Trusty Tar, running unity 5.02 with Wine under PlayOnLinux. It works perfectly.
I will quote you some instruction which can be easily found on youtube
I used simple PlayOnLinux installation! Downloaded the Editor file for
Windows from the Unity site(I took 64-bit). Than I went in Play On
Linux, went to tools > Manage Wine versions and installed Wine 1.7.40
for both x64 and x86. Than I pressed install. On bottom left selected
the install non-listed program. Than I created new virtual drive
called Unity3D, selected the installation bits accorting to the Editor
downloaded(I took 64-bit). After that completed all installation and
made shortcut for Unity.exe. In here I downloaded quick icon, but now
I have set the original icon for it(RC shortcut(.desktop file) and
select icon(press on icon and choose one from your computer). It runs
for me. After that I selected the Unity icon in Play On Linux, pressed
configure, on the top selected section with additional packages,
installed the Microsoft Core Fonts so I can see text in Unity editor.
I also installed Standard Assets from the Unity site like
this:Download the .exe Open Play On Linux Install- Non-Listed program
Update existing virtual drive- Unity 3D Select Wine 1.7.40 Select the
Standard Assets file Install Done, it is installed, don't make any
shortcuts here, leave it as it is, run the Unity and enjoy;)