Guide to Linux Installation and Administration, 2e1 Chapter 7 The Role of the System Administrator

Guide to Linux Installation and Administration, 2e2 Objectives In this chapter, you will: Explain the role of a system administrator Discuss the responsibilities of a system administrator Use basic system administration commands in Linux

Guide to Linux Installation and Administration, 2e3 Working as a System Administrator The role of a Linux system administrator is to keep Linux-based computer systems running efficiently A system administrator works as part of the Information Systems (IS) or Information Technology (IT) department of an organization

Guide to Linux Installation and Administration, 2e4 Working as a System Administrator The IS or IT departments work in two areas: –Internal information systems –Organizational information viewed by the public over the Internet The help desk team directly solves problems for end users

Guide to Linux Installation and Administration, 2e5 The Position of a System Administrator within Small Company

Guide to Linux Installation and Administration, 2e6 The Position of a System Administrator within Large Company

Guide to Linux Installation and Administration, 2e7 Tasks of a System Administrator System administrators perform the following tasks: –Help users solve problems –Train users –Inform management of technical developments –Maintain system hardware –Create new user accounts –Define procedures and policies –Plan systems

Guide to Linux Installation and Administration, 2e8 Ethics and the System Administrator System administrators are trusted employees System administrators have access to valuable personal and business data Legal and ethical rules control work of a system administrator

Guide to Linux Installation and Administration, 2e9 Principles of Maintaining a Linux System Linux utilities are programs used for system administration Linux system is designed to be used by multiple users Each program or system service relies on a separate plain-text configuration file Most Linux command-line utilities are designed to do one task very well

Guide to Linux Installation and Administration, 2e10 Linux Configuration Files Program and system services create and maintain its own configuration information The configuration files for programs managed by the system administrator are stored in the /etc directory Configuration files for programs that are used by only a single user are stored in that user’s home directory

Guide to Linux Installation and Administration, 2e11 Some Configuration Files Used by Linux

Guide to Linux Installation and Administration, 2e12 Advantages of Multiple Plain-Text Configuration Files Using plain-text configuration files has several advantages: –Allow complex configurations –Permit modifications using any text editor –Easy to write a program to manipulate the configuration –Each file is small and independent –Flexibility

Guide to Linux Installation and Administration, 2e13 Advantages of Multiple Plain-Text Configuration Files Other utilities designed to provide a framework for configuring all Linux programs: –KDE –Gnome –Webmin

Guide to Linux Installation and Administration, 2e14 Configuring a Program with a Graphical Utility

Guide to Linux Installation and Administration, 2e15 The KDE Control Center

Guide to Linux Installation and Administration, 2e16 A Gnome Configuration Utility

Guide to Linux Installation and Administration, 2e17 Understanding Files, Devices, and Processes A device is a hardware peripheral Devices are accessed via the /dev directory, either directly or by creating an association with another system resource

Guide to Linux Installation and Administration, 2e18 Understanding Files, Devices, and Processes Processes are the programs running on Linux Program is a piece of software that executes on the Linux system A daemon is a background process A thread is a part of a process, or subprocess

Guide to Linux Installation and Administration, 2e19 Daemons Running on Linux

Guide to Linux Installation and Administration, 2e20 Multiple Users, Multiple Processes Linux supports multiple users working at the same time Each user account can execute multiple programs, and each of these processes is associated with the user that started it System administrator can log in as root to manage all processes on the system

Guide to Linux Installation and Administration, 2e21 Using Small, Efficient Utilities To provide flexibility, Linux commands have numerous options All command options are focused on a single type of task Each option is represented by: –a hyphen followed by a single letter –two hyphens followed by a word describing the option

Guide to Linux Installation and Administration, 2e22 Common Options of the ls Command Options

Guide to Linux Installation and Administration, 2e23 Combining Command Options

Guide to Linux Installation and Administration, 2e24 Standard Input and Output Channels of communication in Linux can be redirected The standard input channel (STDN) data provided by the kernel comes from the keyboard A program sends data to the standard output channel (STDOUT) to display that information on- screen

Guide to Linux Installation and Administration, 2e25 Standard Input and Output Error messages are written to standard error (STDERR) A pipe connects the output channel of one command to the input channel Pipes are used to connect the output of one application to the input of another application

Guide to Linux Installation and Administration, 2e26 Creating a Pipe between Two Applications

Guide to Linux Installation and Administration, 2e27 Redirecting Input and Output

Guide to Linux Installation and Administration, 2e28 Using Basic Administration Tools A system administrator should know about a number of basic Linux utilities and the options supported by those utilities A single utility has a simple function Multiple utilities can be combined together using redirection

Guide to Linux Installation and Administration, 2e29 Case Sensitivity in Linux Everything in Linux is case sensitive Program names and commands in Linux are all lowercase

Guide to Linux Installation and Administration, 2e30 Filenames and File Extensions File extensions can be used for convenience in Linux, but they are not important Filenames in Linux can be up to 256 characters, include most special characters except a forward slash

Guide to Linux Installation and Administration, 2e31 Learning about Linux Commands To learn about Linux commands: –Use a command’s -- help option –View the online manual pages –Use the info command The apropos command can help you locate an appropriate command based on a keyword search of man pages

Guide to Linux Installation and Administration, 2e32 Using Regular Expressions A regular expression provides a flexible way to encode many types of complex patterns Regular expression can be used as parameters to Linux commands Regular expressions operate in the same way as wildcards

Guide to Linux Installation and Administration, 2e33 Common Regular Expressions in Linux

Guide to Linux Installation and Administration, 2e34 Example Regular Expressions

Guide to Linux Installation and Administration, 2e35 Deleting Files in Linux Deleting files using the rm command in Linux is permanent After using rm, deleted files cannot be recovered

Guide to Linux Installation and Administration, 2e36 Deleting Files in Linux To protect users from accidentally erasing files: –Use the safedelete utility –Use the rm command with the –i option, which prompts you for confirmation before deleting a file –Use the trashcan on the KDE or Gnome Desktop –Use a low-level disk editing tool

Guide to Linux Installation and Administration, 2e37 Finding What You Need The locate and find commands help you locate files within Linux The locate command is used to search an index of all files on your Linux system The find command lets you specify properties of the file to match The grep command searches within text files for patterns that you specify using regular expressions

Guide to Linux Installation and Administration, 2e38 Reviewing System Processes Process ID (PID) is a unique number identifying a process The ps command provides a PID and other information about each process running on Linux The kill command is used to end a process

Guide to Linux Installation and Administration, 2e39 Summary The role of a Linux system administrator is to keep Linux-based computer systems running efficiently System administrators maintain end-user systems, Internet systems, train and support users, and solve system problems Each program and service in Linux is configured using plain-text configuration files Graphical configuration utilities are used for system administration A single task performed by a process cab be split into multiple threads, or subtasks

Guide to Linux Installation and Administration, 2e40 Summary Linux supports multiple users working at the same time Communications to and from program is provided by standardized channels STDN, STDOUT, and STDERR To learn about Linux commands, review the online documentation and view command’s options Regular expressions provide a flexible way to encode many types of complex patterns Linux provides the locate, find, and grep tools to help you locate specific files and search within files