Module: EG-253 Practical Internet Technology II

Date of last presentation: 4th October 2007

Presented by: Dr Chris P. Jobling

This lecture is adapted from the lecture created for CS-244 and CS-M74 by Andy Gimblett of the Department of Computer Science.

Introduction to this Component

• Aims and Motivation
• Lectures and Assessment
• Recommended Reading

Aims:

• Understand concepts.
• Know how to use tools and commands.

Motivation:

• C, future modules (eg EG-244, EG-252, EG-259, CS-228).
• Useful in industry.
• Comparative analysis vs. Windows

• 3 lecture/labs on Linux.
• One coursework (10% of EG-253).

• Running Linux (O'Reilly)
• Linux in a Nutshell (O'Reilly)
• Introducing UNIX and Linux (Palgrave Macmillan)
• Linux Documentation Project (www.tldp.org)
  • Introduction to Linux
  • Linux Dictionary
  • Linux Cookbook
• man pages and GNU info (see later).

\section{Introducing Unix}

\subsection{Context \& History}

\begin{frame}

=====Context \& History — Unix}

\begin{itemize}

• 1960s: MULTICS project at AT\&T Bell Labs, abandoned.

• 1960s: UNIX an attempt to capture the best bits.

• Aims:

    \begin{itemize}
    
      * Portable.

• Simple, small, elegant — but powerful.

• Promote code re-use. Small programs, do one thing well.

    \end{itemize}

• Reject ``User Friendly means Easy To Learn. * Assume user knows what they're doing. \end{itemize} \end{frame} \begin{frame} =====Context \& History — GNU To Linux} \begin{itemize} * 1980s: Multiple Unix vendors, jealously guarded IP. * RMS decides to create an open and free Unix-like OS. * GNU Project — responsible for loads of great software. * Early 1990s: Linus Torvalds plays with MINIX, decides to have a go. * Internet facilitates collaboration, Linux takes off. * Linux kernel + GNU tools = Linux we know and love. * Lots of flavours, but open so feed off each other. \end{itemize} \end{frame} \subsection{Unix Essentials} \begin{frame} =====System Overview} \begin{center} \includegraphics[angle=270,width=7cm]{linux_organisation} \end{center} \end{frame} \begin{frame} =====Kernel} \begin{itemize} * Central part of OS. * Concerned with managing hardware and other system resources. * Whatever you do, the kernel is involved. * Never accessed directly by user, however. * Provides access to its facilities via \textbf{system calls}. * Really ``Linux is just the kernel.

\end{itemize}

\end{frame}

\begin{frame}

=====Applications \& Utilities}

\begin{itemize}

  * The programs which access the kernel via system calls.

• Things which make system useful and useable.

• Basically anything that runs on the system.

• One of the two main topics of this course.

• Examples: cp, gcc, slogin, gimp

• One important class of apps: apps for running other apps.

    \begin{itemize}
    
      * Shells

• Graphical Environments

    \end{itemize}

\end{itemize}

\end{frame}

\begin{frame}

=====Shells}

\begin{itemize}

  * The other main topic of this course.

• Command-line environment within which other runs are run.

• Like the DOS Prompt/Command Prompt in Windows.

• Unlike Windows, no single ``best shell, instead lots of choice. * De facto standard in Linux is \textbf{bash}, so we look at that. * Others: sh, csh, zsh, tcsh, ksh, etc. \end{itemize} \end{frame} \begin{frame} =====Graphical Environments} \begin{itemize} * X Window — toolkit for graphics mode programs. * Windows Manager — provides look-and-feel for programs running under X. * Desktop Environment — Extra layer providing comfortable \& easy environment for working. * Not really of concern on this course. \end{itemize} \end{frame} \section{Getting Started with Linux} \begin{frame} =====Getting Started} \begin{itemize} * Logging In — enter username \& password. * Logging Out — just like Windows. (?) * Menu system — should be explored. Try things out. * Running a Shell \begin{itemize} * Look for Terminal}, \texttt{xterm, shell}, \texttt{bash. * Ensure you're running bash. * To exit: exit} or \texttt{Ctrl-d. \end{itemize} \end{itemize} \end{frame} \subsection{Essential Commands} \begin{frame} =====Essential Commands (1)} nb:} \textbf{Case Sensitive!!! \begin{itemize} * ls — List a directory * pwd — Print current working directory * cd — Change directory * cp — Copy a file * mv — Move a file, rename a file * mkdir — Create a directory * rm — Remove a file or directory \end{itemize} \end{frame} \begin{frame} =====Essential Commands (2)} \begin{itemize} * ps — Print processes running * top — Print top processes running * which — Print path to command * file — Print type of file * cat — Print contents of text file * less} / \texttt{more — Read text file one page at a time. \end{itemize} \end{frame} \subsection{Getting Help} \begin{frame} =====Getting Help — man} \begin{itemize} * man pages are canonical source of documentation * man ls} to see manual page for \texttt{ls * Standard form, hard to read at first, but \textbf{essential} skill. * Chapters: ls(1)} means \texttt{ls is in chapter 1. * Read from chapter n} using \texttt{man 1 ls * man -k to search manual pages for some string. \end{itemize} READ THE MAN PAGES!!! \end{frame} \begin{frame} =====Getting Help — info} \begin{itemize} * GNU Project's hypertext-based manual system. * Much more complicated than man pages. * info ls} to get info page for \texttt{ls. * Hit h to start an interactive tutorial. * info on its own for top-level node. \end{itemize} \end{frame} \subsection{Bash Tips \& Tricks} \begin{frame} =====Bash Tips \& Tricks — History} \begin{itemize} * Bash remembers what commands you've typed. * !! to repeat last command. * !-n to repeat nth last command. * Up and down arrows for quick navigation. * history to print numbered history. * Then !n'' to repeat some numbered line.

• Ctrl-r to reverse-search through history.

\end{itemize}

\end{frame}

\begin{frame}

====== Bash Tips \& Tricks — Tab Completion}

\begin{itemize}

  * The Best Thing Since Sliced Bread.

• Bash will guess file \& directory names for you when you hit

tab.

• Guesses as far as it can. Then provide more letters to

remove ambiguity.

• Will give you all the choices if you keep hitting tab.

• An incredible timesaver — you owe it to yourself to use it.

• Can also prevent mistyped filenames.

\end{itemize}

\end{frame}

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