\documentclass{scrreprt}

\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage[ngerman]{babel}

\title{Index Demo}
\author{markus schnalke}
\date{2014-05-05}

%\usepackage{showidx}  % use for index-checking

\usepackage{makeidx}
\makeindex


\begin{document}

\maketitle
\tableofcontents

\chapter{Unix}
Unix
\index{Unix}
is an operating system.
It was invented in the late 60s and early 70s at the AT\&T
\index{AT\&T}
Bell Labs.

% INDEX
%\clearpage
\addcontentsline{toc}{chapter}{Index}
\printindex


\end{document}
