Removing Header and keeping page number

Question

I want to remove page header but keeping the page number with even and odd order. This code is sample of very large code.

        % !TeX spellcheck = en_US

    \documentclass[11pt,twoside]{book}% Use this line for the print version of the thesis
    \usepackage[ngerman,american]{babel}
    \usepackage{blindtext}
    \begin{document}
     \pagestyle{headings}
    \mainmatter
    \include{chapter1}
     \pagestyle{plain}
    \include{chapter2}

    \end{document}

% content
Chapter1


    \chapter{Chapter1}
    \label{chp:1}
    \section{XXX}
    \Blindtext
    \section{YXX}
    \Blindtext

Chapter2


    \chapter{Chapter2}
     \section{XXX}
    \Blindtext
    \section{YXa}
    \Blindtext

I used \pagestyle{plain}. It works but shifts page number to to the bottom center of the page (5-8) which is wrong. I want to keep page number on left and right corner of the pages ( see page 2-4).

• Other questions are:

**why Heading of Chapter 1&2 are appearing double.

Why page number 1 is on the bottom center of the page.**

Answer 1

It is very easy to redefine the plain pagestyle with titleps

\documentclass[11pt,twoside]{book}% Use this line for the print version of the thesis
\usepackage[ngerman,american]{babel}
\usepackage{blindtext}
\usepackage{titleps}
\renewpagestyle{plain} {%
\sethead{}{}{}
\setfoot[\thepage][][]{}{}{\thepage}
}
\pagestyle{plain}

\begin{document}

\mainmatter

\chapter{Chapter1}
\label{chp:1}
\section{XXX}
\Blindtext
\section{YXX}
\Blindtext

\chapter{Chapter2}
 \section{XXX}
\Blindtext
\section{YXa}
\Blindtext

\end{document}

Answer 2

\documentclass[11pt,twoside]{book}% Use this line for the print version of the thesis
    \usepackage[ngerman,american]{babel}
    \usepackage{blindtext}
\makeatletter
  \def\ps@plain{%
      \def\@oddfoot{\hfill\thepage}
\def\@evenfoot{\thepage\hfill}
      \def\@evenhead{}%
      \def\@oddhead{}%
}
  \def\ps@headings{%
      \let\@oddfoot\@empty\let\@evenfoot\@empty
      \def\@evenhead{\thepage\hfil}%
      \def\@oddhead{{}\hfil\thepage}%
      \let\@mkboth\markboth
}
\makeatother
    \begin{document}
     \pagestyle{headings}
    \mainmatter
    \include{chapter1}
     \pagestyle{plain}
    \include{chapter2}

    \end{document}