Operating Systems Basics – 2.8.2 Quiz: Linux Overview
1. A system administrator issues the command ps on a server that is running the Linux operating system. What is the purpose of this command?
- to change file permissions
- to process a new task
- to list the processes currently running in the system
- to display the contents of the current directory
Explanation: The Linux ps command is used to list the currently running processes in the system. If needed, this command can be instructed to display running processes initiated by the current user or other users.
2. Why would a rootkit be used by a hacker?
- to try to guess a password
- to gain access to a device without being detected
- to reverse engineer binary files
- to do reconnaissance
Explanation: Hackers use rootkits to avoid detection as well as hide any software installed by the hacker.
3. Which user can override file permissions on a Linux computer?
- any user that has ‘other’ permission to the file
- only the creator of the file
- any user that has ‘group’ permission to the file
- root user
Explanation: A user has as much rights to a file as the file permissions allow. The only user that can override file permission on a Linux computer is the root user. Because the root user has the power to override file permissions, the root user can write to any file.
4. Which method can be used to harden a device?
- Force periodic password changes.
- Allow USB auto-detection.
- Allow default services to remain enabled.
- Allow users to re-use old passwords.
Explanation: The basic best practices for device hardening are as follows:
- Ensure physical security.
- Minimize installed packages.
- Disable unused services.
- Use SSH and disable the root account login over SSH.
- Keep the system updated.
- Disable USB auto-detection.
- Enforce strong passwords.
- Force periodic password changes.
- Keep users from re-using old passwords.
- Review logs regularly.
5. What is a daemon?
- an application that monitors and analyzes suspicious activity
- a type of security attack
- a record to keep track of important events
- a background process that runs without the need for user interaction
Explanation: A daemon in Linux is a background process that runs without the need for user interaction. A network administrator can view log files in order to see information about daemons running on the Linux server.
6. A system administrator issues the apt-get upgrade command on a Linux operating system. What is the purpose of this command?
- Every application installed will update itself to the latest version.
- A specific application named upgrade will be installed.
- The remote repository of applications and dependencies will be updated to the latest version.
- Operating system updates are downloaded and will be installed.
Explanation: When the apt-get upgrade command is issued in a Linux terminal, all installed applications will attempt to upgrade to the latest version available.
7. In the context of a Linux operating system, which command can be used to display the syntax and parameters for a specific command?
- cat
- grep
- man
- crontab
Explanation: The functions of listed CLI commands of a Linux system are as follows:
cat – lists the contents of a file
man – displays the documentation for a specific command
crontab – manages the cron service for scheduling system tasks
grep – searches for specific strings of characters within a file or other commands outputs
8. A technician has captured packets on a network that has been running slowly when accessing the internet. Which port number should the technician look for within the captured material to locate HTTP packets?
- 20
- 80
- 110
- 21
- 53
Explanation: HTTP uses TCP port 80 and HTTPS uses TCP port 443. HTTP and HTTPS are protocols commonly used to access web pages.
9. Which file system is the primary file system used by Apple in current Macintosh computers?
- CDFS
- APFS
- ext3
- ext2
- HFS
Explanation: The primary file system used by Apple in its lates Macintosh computers is APFS.
10. Which type of tool is used by a Linux administrator to attack a computer or network to find vulnerabilities?
- firewall
- intrusion detection system
- PenTesting
- malware analysis
Explanation: PenTesting is known as penetration testing and includes tools that are used to search for vulnerabilities in a network or computer by attacking it.
11. Which Linux command can be used to display the name of the current working directory?
- sudo
- chmod
- pwd
- ps
Explanation: One of the most important commands in Linux is the pwd command, which stands for print working directory. It shows users the physical path for the directory they are working in.
12. Why is Kali Linux a popular choice in testing the network security of an organization?
- It is a network scanning tool that prioritizes security risks.
- It can be used to test weaknesses by using only malicious software.
- It is an open source Linux security distribution containing many penetration tools.
- It can be used to intercept and log network traffic.
Explanation: Kali is an open source Linux security distribution that is commonly used by IT professionals to test the security of networks.
13. What are three benefits of using symbolic links over hard links in Linux? (Choose three.)
- They can be compressed.
- They can link to a file in a different file system.
- They can show the location of the original file.
- Symbolic links can be exported.
- They can be encrypted.
- They can link to a directory.
Explanation: In Linux, a hard link is another file that points to the same location as the original file. A soft link (also called a symbolic link or a symlink) is a link to another file system name. Hard links are limited to the file system in which they are created and they cannot link to a directory; soft links are not limited to the same file system and they can link to a directory. To see the location of the original file for a symbolic link use the ls -l command.
14. What is a benefit of Linux being an open source operating system?
- Linux distributions are maintained by a single organization.
- Linux distribution source code can be modified and then recompiled.
- Linux distributions are simpler operating systems since they are not designed to be connected to a network.
- Linux distributions must include free support without cost.
Explanation: Linux is an open source operating system and any person can access the source code, inspect it, modify it, and recompile it. Linux distributions are maintained by a community of programmers and are designed to be connected to a network and do not have to provide free support.
15. Consider the result of the ls -l command in the Linux output below. What are the group file permissions assigned to the analyst.txt file?
ls –l analyst.txt -rwxrw-r-- sales staff 1028 May 28 15:50 analyst.txt
- read only
- read, write
- read, write, execute
- full access
Explanation: The file permissions are always displayed in the User, Group and Other order. In the example displayed, the file has the following permissions:
- The dash (–) means that this is a file. For directories, the first dash would be replaced with a “d”.
- The first set of characters is for user permission (rwx). The user, sales, who owns the file can read, write and execute the file.
- The second set of characters is for group permissions (rw–). The group, staff, who owns the file can read and write to the file.
- The third set of characters is for any other user or group permissions (r–). Any other user or group on the computer can only read the file.