This is a plugin for Kate which adds two buttons on the toolbar: "Run LaTeX" and
optionally "View Output" (of course you can add or remove these buttons in the
"Configure Toolbars" dialog). The first button runs LaTeX (and runs BibTeX,
MakeIndex, and reruns LaTeX if necessary; optionally the viewer is launched
after this), the second button opens the output in the viewer of your choice. 

The paths to the executables can be modified in the Settings
dialog (see second screenshot).