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This presentation covers :  User Interface Administration  Files System and Services Management 2

User Interface Administration 3

 Users can log on to a Linux operating system using the Command-Line Interface (CLI).  The Linux CLI provides the user with successive text only prompts to enter a user name and password.  No additional domain information is required. 4

 "X Window" allows Linux to operate similar to the other GUIs.  A typical X Window interface will look somewhat familiar to a Windows user.  Linux users can completely customize their X Window interface to meet their specific needs. 5

 The Linux command-line interface (CLI) allows the user to interact with the system in the same manner as the Windows command prompt.  Users should try entering basic commands.  Do not attempt to randomly guess commands, since such careless activity could have impacts on the system. 6

 The man command displays online manual pages for any of the hundreds of Linux commands.  A listing of all the Linux commands with a brief description of what they do can be obtained by entering man intro at the command line.  A man page can be displayed on the man command itself by typing man man. 7

 A number of different headings or informational areas are in a typical man page.  All commands will have at least a name, a synopsis, and a description.  A common Linux command is cd, which allows users to change directories. 8

 The ls command can be issued with the [options] and the [files] list to display the contents of a specific directory.  When the ls command is issued without these options the contents of the current directory will be listed.  Also more than one filename can be given so that the ls command will list the contents of multiple directories. 9

 The Linux shells operate as a command interpreter.  The command interpreter from the MS-DOS environment is similar.  It combines the interactive features that make the C shell popular with the easier to use shell programming syntax of the Bourne shell.  The Born Again Shell is referred to as the bash shell and is used for many ’UNIX-like’ systems. 10

Files System and Services Management 11

DIRECTORY SUB-DIRECTORY1 SUB-DIRECTORY2 FILE DATA Linux uses a hierarchical file system نظام الملفات المتدرج (الشجري) Directories contain sub- directories Directories and sub- directories hold files 12

ROOT DIRECTORY / BIN BOOT DEV ETC HOME MOUNT PROC USR ROOT SBIN TMP Amal Muna Maha Nada Pictures Downloads Books Videos 13

ROOT /dev /boot /bin /pro c /mnt /etc /home /lib /root /sbin /usr /var /tmp 14

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 Creating files and directories in Linux is a matter of knowing the proper commands and how to use them.  Some of the commands use the same syntax for both files and directories, while others are different. 17

 The find command is used to locate one or more files assuming that you know their approximate filenames.  The find command lets you specify filters, and run commands on the contents of entire directory trees.  The grep command allows you to search for a pattern in a list of files.  The way to search for a string with the grep command is to put the words you are searching for together in single quotes. 18

This presentation covers :  User Accounts and Group Accounts  Files System configuration files  Benefits of Networking  Daemons 19

User Accounts and Group Accounts 20

 User accounts in a Linux system allow several people to be logged into the system at the same time or at different times without interfering with each other.  The term user and account are sometimes used interchangeably.  There are several important terms that will need to be learned. 21

 The Linux operating system is both a multiuser and multitasking system.  The most important user account is the Superuser account; also referred to as the root account.  This account is used by the system administrator to perform any administrative tasks on a Linux system.  The Superuser account can be used in several ways: ◦ root login ◦ Su ◦ Sudo ◦ SUID root files 22

 The root user creates other Linux users with the useradd command.  When this command is entered at the prompt, Linux performs many simultaneous tasks to create the user account, such as creating a home directory and assigning default permissions.  Flags and parameters exist for the useradd command and can be found by viewing its man page. 23

 Use the useradd command useradd  Use the passwd command to set password passwd  Try it… logon as root root useradd amal passwd amal Changing password for user amal New UNIX password: Retype new UNIX password: passwd: all authentication tokens updated successfully 24

 The process of disabling an account requires a bit more effort.  The system administrator must edit the file that stores all user information on the system and manually disable the user's password.  User passwords are stored in a central file known as the ‘shadow’ file, which is located in the /etc directory. vi  This file can be edited with a text editor like vi Editor. 25

 Every group on a Linux system can have anywhere from no members to as many members as there are user accounts on the systems.  Group membership is controlled by the /etc/group file.  To change to a different group after logging into the system use the newgrp command.  The syntax for this command is newgrp for example: newgrp engineering.  The gpasswd command can be used to modify existing groups. 26