operating system deck 4- Linux commands

Question 1

You need to view the processes running on a Linux system. Which command should you use?

Answer 1

The ps command provides a list of current processes running on the system.

Question 2

grep

Answer 2

allows you to search for a pattern of text within one or more files. For example, you could find the characters “pwd” in file1.txt, file2.txt and file3.txt by entering the grep pwd file1.txt file2.txt file3.txt command.

Question 3

apt-get command

Answer 3

allows you to manage packages within Ubuntu.

Question 4

chmod command

Answer 4

allows you to change permissions on a file. The basic syntax is chmod user=Permission List filename. The user parameter can be u for you, g for the group, or o for other. The permission list parameters include r for read, w for write, x for execute, and - for no access. For example, the chmod u=rwx,g=r-x, o=r– myspecialfile command would give the user read, write and execute access, the group read and execute access, and others read access only.

Question 5

apt-get

Answer 5

allows you to work with the Advanced Packaging Tool and install packages (applications) in Ubuntu, which is a Debian-based distribution.

Question 6

cat

Answer 6

displays the contents of one or more files without having to open the file for editing.

Question 7

cd

Answer 7

changes directory. It is similar to the Windows cd command. For example, the cd / moves you to the root directory, and cd.. moves you to the parent directory.

Question 8

chmod

Answer 8

changes the permissions on a file. The basic syntax is chmod user=PermissionList filename. The user parameter can be u for you, g for the group, or o for other. The permission list parameters include r for read, w for write, x for execute, and – for no access. For example, the chmod u=rwx,g=r-x, o=r– myspecialfile command would give the user read, write and execute access, the group read and execute access, and other users read access only.

Question 9

chown

Answer 9

changes the ownership of the file. For example, the chown mrhacker mypassword.txt command would give the mrhacker user ownership of the mypassword.txt file.

Question 10

cp

Answer 10

copies files and directories.

Question 11

dd

Answer 11

allows you to copy a file and convert it to another format during the copying process.

Question 12

df

Answer 12

gets a full summary of available and used disk space of the file system.

Question 13

dig

Answer 13

queries the Domain Name System for troubleshooting purposes as well as will display the DNS information.
find –locates files based on the user-specified criteria and either prints the pathname for the matched object or can perform actions on the matched object depending on the parameters the user put into place.

Question 14

grep

Answer 14

finds a pattern of text within a file or group of files. For example, you could find the characters “pwd” in file1.txt, file2.txt and file3.txt by entering the grep pwd file1.txt file2.txt file3.txt command. iwconfig / ifconfig – analogous to the ipconfig command. The ifconfig command is used to view and configure network interfaces. The iwconfig command is similar to the ifconfig command, but is restricted to wireless interfaces.

Question 15

ls

Answer 15

lists file and directory contents.

Question 16

IP

Answer 16

shows or manipulates routing, devices, and tunnels that are connected to a device.

Question 17

man

Answer 17

displays the user manual of any command that the user can run on the terminal. It provides a detailed view of the command manual displaying the name, synopsis, description, files, errors, versions, and other similar information.

Question 18

mv

Answer 18

renames or moves a file.

Question 19

nano

Answer 19

a small, free editor that replaces the default editor, Pico. Nano improves upon pico by implementing features like “search and replace” and “go to line number.”

Question 20

ps

Answer 20

provides a list of current processes running on the system.

Question 21

pwd vs. passwd

Answer 21

The pwd command displays the working directory, or the directory that you are currently in. On the other hand, the passwd command allows you to change the password of a user account.

Question 22

q

Answer 22

quits (exits) the vi editor. By itself, the q command will allow you to exit the editor if no changes have been made to the file. If you have made changes to the file and wish to keep the changes, enter wq. If you wish to discard the changes, enter q!.

Question 23

top

Answer 23

displays information about the CPU and memory utilization.

Question 24

rm

Answer 24

removes a file.

Question 25

shutdown

Answer 25

turns off the computer. Adding the /h parameter to the command halts the shutdown and adding the /r parameter to the command reboots after shutdown.

Question 26

su/sudo

Answer 26

The su command allows you to log on as the superuser (root). The sudo command allows a regular user to execute commands as the superuser.

Question 27

vi

Answer 27

the text editor in Linux. To edit a file, enter the vi filename command.

Question 28

yum

Answer 28

An interactive package manager that can automatically perform system updates, perform dependency analysis, remove old packages, and perform queries.