CENT 305 Information Systems Security Linux Introduction

Open SUSE OS A “distro” of the Linux OS, which is a “flavor” of Unix OS. A multiuser, multitask, both GUI and command-line interface OS Graphical environments similar to Windows/Mac, with (free!) Open Source Office Command line environment similar to Windows DOS and uhunix.hawaii.edu Open source software Popular in European markets Purchased recently by Novell Now commercially available as enterprise operating system Software is still open source --- i.e., the code is freely available for modification OpenSUSE Linux versions 12 and 11 Open source (free) version supported by SUSE Can be downloaded and installed at home for no charge - also available in Live CD format. Gerald has copies of the Live CD for the KDE and Gnome environments. Comparable to Enterprise (Server) and Desktop versions combined References Online references will be posted on course web site Getting Started with Linux; Novell's Guide to CompTIA's Linux+, Novell & Jason Eckert, Thomson Course Technology, 2007, ISBN-10: X 2

Objectives Familiarity with Linux interfaces ◦ Graphical User Interface ◦ Command Line Interfaces Be able to use basic Linux features ◦ bash shell - command line interface ◦ vi (command line) text editor ◦ basic scripts 3

Graphical User Interface (Demo) Login Screen ◦ Menu options ◦ Shutdown/restart KDE desktop features ◦ KDE control panel (Kicker)  KDE menu, Konqueror, Terminal Emulation ◦ KDE menu ◦ KDE Desktop 4

Command Line Interfaces Virtual Terminals ◦ CTL-ALT-F# ◦ Consoles F1-F6 are command line interfaces ◦ Console F7 is the graphical interface ◦ Each console is independent of the others Terminal Windows (Konsole, and others) ◦ Accessed as a shell window in the graphical interface. ◦ Provides an emulation of a virtual console. Important: Unix command syntax: command [-options] arguments ◦ Example: ls –R mydir ◦ Example: cp file1 file2 5

Linux Help Resources man pages ◦ online reference manuals ◦ Syntax: man [-k] whatyouarelookingup ◦ example:man ls ◦ example: man –k backup ◦ Uses the less pager for navigation (man less) info pages ◦ more sophisticated navigation than man pages (info info) Release notes ◦ /usr/share/doc/release-notes How-to files (Linux Documentation Project) ◦ /usr/share/doc/howto/en/html or txt Package help files ◦ /usr/share/doc/packages/package-name 6

YaST Management Utility Yet Another Setup Utility Works with command line or graphical environment Allows management of ◦ Software packages ◦ User & Group Accounts ◦ Printer Configuration ◦ View Hardware Configuration ◦ X Windows configuration 7

Command Shells The command shell program provides the command line interface in a non-graphical environment. ◦ Accepts commands entered by the user on the command line. ◦ Runs the specified command and displays the result on the screen. ◦ Also called the command interpreter. Linux supports a variety of shells: ◦ bash - the Bourne Again SHell, default Linux shell ◦ sh- the Bourne SH, the original UNIX shell ◦ csh- the c shell (Open SUSE 11 uses tcsh) ◦ ksh- the Korn shell ◦ zsh- the z shell 8

Using the Command Line Start a shell window (Konsole) Using commands --- previous examples... Pipes and redirection ◦ cat /etc/passwd | less (pipe) ◦ cat /etc/passwd > mypasswd.txt (redirect, i.e. put into) ◦ cat /etc/group >> mypasswd.txt (append) 9

Text Editors Needed for editing Linux configuration files, which are usually ASCII text files. Graphical text editors ◦ gedit, kwrite, kate, etc.... ◦ Work fine as long as there is a GUI... Terminal based text editors ◦ vi (and its improved version vim), emacs, pico ◦ MUST be used in a command-line environment such as a virtual console – why? 10

Overview of Terminal Based Text Editors vi or vim ◦ Most commonly used by system administrators ◦ Moderately complex and powerful tool. ◦ Installed by default on ALL UNIX/Linux systems --- so it's always available ◦ Must know it, in case nothing else is available emacs ◦ Frequently used by programmers. ◦ Very complex to learn and use and very powerful. ◦ May NOT installed by default and is not always available. pico ◦ Simple, menu-driven text editor ◦ Easy to learn and use. ◦ Not very powerful. ◦ May not always be installed, but usually is. 11

vim intro vi visual editor commonly used Unix text editor vim vi improved updated version of vi that’s somewhat easier to use default version of vi provided with Linux 12

vim basics vim filename creates and new file and opens it for editing vi modes command mode --- used for entering commands, saving files, and quitting vi insert mode --- used for entering text Laulima includes a summary of vi commands Review: type up a simple text file in vim and try different formatting. 13