It seems like the default file manager in ubuntu 12.04 -> nautilus does not have a file preview option! This is a really important requirement for me and I am missing the good old file preview pane in windows 7 or macOSX.
There are a few options in ubuntu for instance gloobus-preview but then it is activated when we press the space-bar and the preview occupies the center of the screen, so it almost blocks the view. Now, is there any way i can install an add-on may be to the nautilus manager in ubuntu 12.04 and get this side-pane for previewing files. What are the other options available otherwise?