Lesson 6A Managing Linux

Question 1

Shell

Answer 1

Provides a command environment by which a user can operate the OS and application.(Bash, zsh, and ksh(Korn Shell))

Question 2

Terminal

Answer 2

Software that implements input and output for a command shell. The Terminal and the Shell are connected by a teletype device.

Question 3

stdin(0)

Answer 3

Takes the user’s keyboard input and writes it as data to the tty device for processing by the shell command interpreter.

Question 4

stdout(1)

Answer 4

Reads data generated by the shell from the tty device and displays it through the terminal.

Question 5

stderr(2)

Answer 5

Carriers error information.

Question 6

Console Switching

Answer 6

Device that implements input and output for a command shell.
CTRL+ALT+Fx keys can be used to switch consoles.

Question 7

Commands

Answer 7

The first “word” input is interpreted as the command.
Options(switches) - Are used to change the operations of a commands.
Arguments- Values supplied to the command for it to operate on, such as file names.
Pipe command(|)- Allows the usage of two commands.

Question 8

Case Sensitivity

Answer 8

Commands, Parameters, and files and directory names are all case sentitive in Linux.
ls -l and ls-L will produce different outputs.

Question 9

Help System

Answer 9

Reports the functions and syntax when executed as –help. Ex. ls –help | more

Question 10

Nano

Answer 10

Nano text editor. nano filepath or nano -| filepath showing line numbers.
CTRL+O writes changes to the files.
CTRL+X quits the editor.

Question 11

Vi or Vim

Answer 11

Preferred by Administrators
Switches
i - switches to insert mode at the current cursor position.
a- appends text after the current position.
A- appends text at the end of the current line
o- insert text on a new line below the current line.
ESC key- switches from insert mode back to command mode.
: set number- Shows line numbers in command mode.
:w- saves the file.
:wq- saves and quits
:q! - quits without saving

Question 12

Navigation Commands

Question 13

pwd Command

Answer 13

Print the working directory that you are currently using.

Question 14

cd Command

Answer 14

Used to change directory.
cd /etc leads to an absolute directory.
cd document leads to subdirectory(relative path) named documents.
cd ..

Question 15

ls Command

Answer 15

List the contents of the directory
Switches
-l - displays a long list
-a - displays all files including the hidden ones.

Question 16

cat Command

Answer 16

Returns the content of the files listed as arguments.
Switches
-n- adds line numbers to the output.
Overwrite = cat > file
Append = cat&raquo_space; file

Question 17

Search Commands

Question 18

find Command

Answer 18

is used to search for files.

Question 19

grep Command

Answer 19

Used to search and filter the contents of a file.

Question 20

File Management Commands

Question 21

cp Command

Answer 21

Used to create a copy of a file in the same or a different directory with the same name or a different name.

Question 22

rm Command

Answer 22

Can be used to delete files.
-r can be used to delete a directory

Question 23

mv

Answer 23

Used to either move a file from one directory to another or to rename a file.

Question 24

df Command
Disk Free

Answer 24

Enables to see the disks free space, file system, total size, space used, percentage valuie of spaced used, and mount point.

Question 25

du Command Disk Usage

Answer 25

Displays how a device is used, including the size of a directory tree.

Question 26

User Account Commands

Question 27

su Command

Answer 27

Used to switch users: su username su - will prompt the superuser account.

Question 28

sudo Command

Answer 28

allows any account listed in the /etc/sudoers file user to run specified commands with superuser privilege level

Question 29

User Management Commands

Answer 29

useradd- add user data usermod- modify user data userdel-delete user data

Question 30

Group Management Commands

Answer 30

groupadd groupmod groupdel Used to manage group permissions

Question 31

File Permissions Commands

Question 32

Read Write Execute

Answer 32

(r)Gives permission to view the content of a file or directory. (w) Gives permission to modify or delete the file. (x) Gives permission to run an executable file or script.

Question 33

Permissions expressed numerically

Answer 33

Read = 4 Write = 2 Execute = 1 Denied = 0

Question 34

chmod

Answer 34

Can be used to secure files and directories, using either symbolic notation o roctal notation. Only the owner can change permissions.

Question 35

chown Command

Answer 35

Allows the superuser to change the owner of a file or a directory. Can only be used by a superuser or sudoer.

Question 36

Package Management Commands

Question 37

apt-get update Command

Answer 37

Refresh the local database with information about the packages available from the repository.

Question 38

apt-get upgrade Command

Answer 38

C

Question 39

apt-get install PackageName

Answer 39

Installs a new application.

Question 40

yum check-update

Answer 40

Refresh the local database with information about the packages available from the repository.

Question 41

yum update

Answer 41

Refresh the local database with information about the packages available from the repository.

Question 42

yum install PackageName

Answer 42

Installs a new application.

Question 43

Process Monitoring Commands

Answer 43

Every process is assigned a unique Process ID when it is started so that the system can identify the process.

Question 44

ps commands

Answer 44

Invokes a process table, a record that summarizes the currently running programs on a system.

Question 45

top Command

Answer 45

List all the processes running on a Linux System. It acts as a process management tool by enabling you to prioritize, sort, or terminate processes interactively.

Question 46

Top Options

Answer 46

ENTER Refresh the status of all processes. SHIFT+N Sort processes in the decreasing order of their PID. M Sort processes by memory usage. P Sort processes by CPU usage. u Display processes belonging to the user specified at the prompt. q Exit the process list.

Question 47

Network Management Commands

Question 48

ifconfig

Answer 48

Part of the legacy net-tools package Safely be used to report the network interface configuration.

Question 49

ip addr

Answer 49

replicates the basic reporting functionality of ifconfig report a single interface only, use ip addr show dev eth0

Question 50

ip link

Answer 50

ip link command shows the status of interfaces, while ip -s link reports interface statistics.

Question 51

dig command

Answer 51

Utility to query a DNS server and return information about a particular domain name or resource record.

Question 52

Samba

Answer 52

Linux software package that implements Server Message Block (SMB) file/print sharing, primarily to support integration with Windows hosts.

Question 53

Backup and Scheduling Commands

Answer 53

In Linux their is no official "backup". Cron can be used as a task scheduler and file copy scripts.

Question 54

crontab -l

Answer 54

Reviews a user's contab job.

Question 55

crontab -r

Answer 55

Remove jobs from the scheduled list.

Question 56

crontab -e

Answer 56

uses the vi editor Basic syntax for scheduling a job. mm - minutes (0-59) hh- hours(0-23) dd- days (0-31) MM- months(1-12) or jan, feb, mar weekday- (day of the week(1-7 or mon, tue, wed)) command-command or script to run (include the file path)