Adding support should be fairly simple. 2 small changes to add:

Do you have access to a Unity3d installation on a Linux host ?

If so, can you give me the following information:

• relative path of the executable from the UNITY_HOME directory. See

          private static File getExeFile(File unityHome) {
              if (Functions.isWindows()) {
                  return new File(unityHome, "Editor/Unity.exe");
              } else { // mac assumed
                  return new File(unityHome, "Contents/MacOS/Unity");
              }
          }
  

• standard location of the Editor.log file
  (e.g. http://docs.unity3d.com/Manual/LogFiles.html)

          if (Functions.isWindows()) {
              [....]
              File applocaldata = new File(localAppData);
              return new File(applocaldata, "Unity/Editor/Editor.log");
          } else { // mac assumed
              File userhome = new File(EnvVars.masterEnvVars.get("HOME"));
              return new File(userhome, "Library/Logs/Unity/Editor.log");
          }
      }
  

Thanks

The relative path to the unity executable is: "Editor/Unity"
The full path in my case is: "/opt/Unity/Editor/Unity" (just in case you need it)

The default Editor.Log path relative to the user home (e.g. "~/") is: ".config/unity3d/Editor.log"
The full path to the Editor.Log is: "/home/jony/.config/unity3d/Editor.log" (again just in case you need it)

You can take your time with the modifications since the Linux Editor still has quite a few issues and it wont even start when you try to run it on an Ubuntu Server installation (See: http://forum.unity3d.com/threads/qxcbconnection-could-not-connect-to-display.352536/). They might also change other settings like the default location of the Editor.Log etc. since this is still a really early experimental build of the Editor.

Code changed in jenkins
User: Jerome Lacoste
Path:
src/main/java/org/jenkinsci/plugins/unity3d/Functions2.java
src/main/java/org/jenkinsci/plugins/unity3d/Unity3dInstallation.java
http://jenkins-ci.org/commit/unity3d-plugin/648a04680f9a6503ea46c8c5444a84adc161a7a8
Log:
JENKINS-30321: Unity Linux Editor Support (completely untested)

Jony, be my guest if you want to try the latest build (not yet released). See the above commit.

Hey lacostej, the plugin seems to invoke Unity but I get the "QXcbConnection: Could not connect to display" error which i mentioned above i guess the jenkins user is not allowed to start graphics devices . After that error i get the warning:
WARNING: No change detected to Editor.log path: '/var/lib/jenkins/.config/unity3d/Editor.log'.
The unity3d plugin was probably unable to find it in its expected locations (see JENKINS-24265).
Which makes sense because Unity never really started to create it in the first place, so i wouldn't worry about it for now.
Thanks for the quick addition to this awesome plugin...now Unity Technologies needs to get to work and fix that bug, i will do more testing if they do so and report back if i find issues with the plugin itself. Until then have a nice day

Jony, I added a reply to your post on the Unity forum with some potential troubleshooting steps. I'll try to set up a Linux server here in the mean time.

Fixed. Coming in next release (1.2)