Change chapter heading and insert line at top of pages.

Question

I'm using this preamble:

\documentclass[pdftex,10pt,b5paper,twoside]{report}
\usepackage[lmargin=25mm,rmargin=25mm,tmargin=27mm,bmargin=30mm]{geometry}
\usepackage[comma]{natbib}
\usepackage{lmodern}
\usepackage{setspace}
\usepackage{amsmath,amssymb,amsfonts} 
\usepackage{graphics}                 
\usepackage{color}              
\usepackage{hyperref}             
\usepackage{graphicx}
\usepackage{listings}
\usepackage{courier}             
\usepackage{longtable}
\usepackage{rotating}
\usepackage{calc}
\usepackage{caption}
\usepackage{booktabs}
\usepackage{ctable}
\usepackage{mathtools}

My problem is that I do not have enough time to completely redo the layout of the hole report, but I would like to fix to things.

1. How do I remove "Chapter" heading and replace it with \chapter{THIS}. Like:

   1 Introduction
   
   text text text text text text text text text
   

   instead of:

   Chapter 1
   
   Introduction
   
   text text text text text text text text text
   

   Also, I need the "new" heading to be placed at the "Chapter" position.

2. How do i make a line at the top of the pages telling which "chapter" you're in. (not in the appendices though)

Answer 1

Both requirements can be achieved with the help of the titlesec package (make the necessary adjustments to suit your needs):

\documentclass[b5paper,twoside]{report}
\usepackage[lmargin=25mm,rmargin=25mm,tmargin=27mm,bmargin=30mm]{geometry}
\usepackage[pagestyles]{titlesec}
\usepackage{lipsum}% just to generate filler text

\titleformat{\chapter}[block]
  {\normalfont\huge\bfseries}{\thechapter}{20pt}{\Huge}
\titlespacing*{\chapter}{0pt}{50pt}{40pt}

\newpagestyle{mystyle}{
  \sethead{\thechapter\  \chaptertitle}{}{}
  \sethead{}{\thepage}{}}
\pagestyle{mystyle}

\begin{document}

\chapter{Test chapter}
\section{Test section}
\lipsum[1-30]

\end{document} 

You can use \pagestyle{plain} in the body of your document, just before the appendices, to restore the plain page style.

EDIT: the pdftex option shouldn't be gived (modern LaTeX systems automatically detect the driver used). Also, the 10pt option is used by default, so you could safely write

\documentclass[b5paper,twoside]{report}