Debian Interview Questions and Answers

1. What is Debian?

Debian is a widely used operating system available as an open-source. It uses the Linux kernel, and other components of Debian are obtained from the GNU project. You can download Debian for any system via the internet, and it will be of minimal cost. In addition, you can get it on CD. Debian being an open-source project has been contributed by more than 500 programmers. It gets updated via new releases from time to time. Debian supports various applications, extensions, and features.

2. Why should you use Debian?

Following are reasons to choose the Debian operating system:

• Debian is a well-known Linux distribution due to its stability and dependability. If you want to run old codes, the stable version of Debian is suitable for running them with its support for older software.
• Debian often provides new releases, giving you time to use the same version for a longer period and leverage its features.
• Debian is one of the most stable, robust, flexible, and perfect distros for the server. In addition, your server need not be connected to the web, and your Wi-Fi network will be enough to power your server.
• Debian comes with support for various architectures. You can run it on 32-bit and 64-bit systems.
• Debian offers one of the largest software repositories, among other alternatives.

3. List down the limitations of Debian.

Following are a few limitations of using Debian:

• It is somehow conservative and lacks some of the important features. It takes time for new releases with updates, so you need to wait for new features.
• Debian is a distro well-suited for admins and developers. However, new users may not find it efficient to start.
• You will get a basic GUI framework, and all the major tasks are done in the terminal.
• You will get less enterprise support, documentation, and other documents.

4. Why do you use Debian?

Following are the various reasons for using Debian distribution:

• Debian is one of the most stable, robust, reliable, and dependable Linux distributions in the market.
• It allows you to use each version for a long time due to its long release cycle.
• Debian is well-suited for running and managing servers.
• It comes with the support for many PC architectures, making it suitable for any type of hardware.
• Among all other Linux distributions, Debian has a strong and vast active community supporting it actively.
• It comes with support for various software.
• It allows installing its free version for any type of operating system and machine.
• For running Debian, maintaining a good internet connection is not required.
• Debian is available as a desktop Agnostic.

5. What are all package managers in Debian?

There are three package managers available for Debian distribution:

• dpkg: It is a package manager for Linux distribution Debian. Whenever you use the apt or apt-get, they will invoke the dpkg program to install or remove the applications and additional functions. Apart from this, they will list the programs and their related information.
• apt/apt-get: It is a better package than dpkg as it helps resolve the dependencies and automatically downloads the software updates. If you want to download any software, it will point to various software repositories stored at /etc/apt/sources.list. After the Debian installation, you need to edit this file with the comment that points to the Debian DVD/USB installation path and add the appropriate repositories. The apt/apt-get- it is a better package than dpkg, since it helps resolve the dependencies and automatically downloads the software updates.
• aptitude: It is somehow similar to the apt package manager. You can access this package manager via the command line. It even allows starting downloading and installing software in an interactive mode within the terminal. This interactive mode will allow to check and browse packages depending on their status, install, and remove packages.ine.

6. What is an Uncomplicated Firewall?

An uncomplicated firewall or UFW is a simple firewall mechanism that can be effectively implemented on the iptables. Configuring an uncomplicated firewall is much easier than configuring iptables. In short, it is a program that helps in managing the Netfilter firewall aiming to provide an interactive user interface for various types of users.

7. When should you use a different Linux distribution?

Well, choosing any particular Linux distribution depends on your requirements. Here are some Linux distributions that you may consider as per thrift benefits and features:

• Fedora: If you are an RHEL developer, then go for the Fedora Linux distribution. Use Fedora as a testing platform for RHEL. It is one of the widely popular Linux distros and offers advanced features. It may not be the most stable distribution, but it is fun to work with.
• Ubuntu Gnome: This distribution provides the combined benefits of Ubuntu reliability and Gnome desktop. It comes with all the good aspects of Ubuntu, along with the largest repository of applications. Apart from this, it offers a broad and strong community. One can even leverage the features of the Evolution mail client that syncs efficiently with Microsoft Exchange Mail and calendar features.
• Debian: It is one of the latest available Linux distributions. You may not get a wide range of features, but it is widely recommended due to its stability.

8. What are the common issues experienced by a Debian server?

Following are some issues that a Debian server may suffer:

• Check if you have a pre-installed web server.
• Check if your web server is running appropriately or not.
• Check for the web server’s configuration files, if they are correct or not.
• Check if your configured ports are open or not.
• Check if your DNS settings are pointing you to the right place.
• Check for the permission and ownership of your server files and directory.
• Check the connection to the database.
• Check if the backend of the server is running properly.

9. Where are the Debian services stored?

In Debian, the services are stored at the path /etc/init.d that helps store scripts and services running at boot or through the system directory /etc/systemd/system/.

10. What are the types of network files stored in Debian?

Here are some network files with their locations:

• For DNS resolution, check- /etc/resolv.conf

• For hostname file, check- /etc/hostname
• For hosts and IP address, check association,check- /etc/hosts
• For managing the network interfaces, check- /etc/network/interfaces
• For checking additional network-related services, check- /etc/init.d

11. How can you solve connectivity-related issues with Debian?

You can solve various following issues as mentioned:

• ifdown<device> : Run this command for turning the network device down.
• ifup <device> : This command will help in turning up the network device.
• dhclient <device> : Check DNS, and run this command for renewing the dynamic IP.
• nano /etc/resolv.conf: This command will help in monitoring your DNS.
• ip route: This command will help in checking your gateway.
• ip show: Use this command for checking your network device’s status, device’s IP addresses, and subnets.
• iptables: This command will help in checking the firewall rules.
• traceroute: This command helps to use traceroute for diagnosing where the connectivity problem happens.
• ping: This command will help you to ping gateways, local network devices, and the internet.

12. How can you update a Debian version?

It can be done by editing the source.ist file along with the repositories for the new available distribution, update it, upgrade all the included packages, and then run the apt full-upgrade. After completing this process, reboot the system to make the changes permanent.

13. What are the listing packages installed on Debian?

One can use any of the two ways for listing the installed packages on Debian. Run the following commands for getting a list of all the packages installed on Debian:

• Dpkg-l
• apt list

14. How do you change a Debian’s desktop environment?

For changing Debian’s desktop environment, use the command tasksel. After running the command, click OK to continue.

Then, choose any distribution from the list by pressing the tab and then select OK and hit enter. Installation would start:

After installation, you need to reboot the system.

15. List down the Features of Debian.

Following are a few listed features of Debian:

• It allows several users to access the same system resources like memory, disk, etc. through different terminals.
• It helps in performing various tasks simultaneously by utilizing the CPU resources.
• It allows the support for various hardware.
• It ensures security using authentication, authorization, and strong encryption.
• It offers keyboards that support different languages.
• It offers a software repository, allowing you to download and install applications.
• It is an open-source distribution that is available for every user.

16. What are the differences between the distributions Debian and CentOS?

Following are the significant differences that you can find between the Debian and Centos distributions based on different aspects.

18. Where can you run Debian?

One is allowed to run Debian on anything. A developer can run Linux on any system under the sun or iPhone, or a Microsoft Xbox 360. However, what if one is not a programmer but a simple user and wants to run Linux? In such case, Debian would run on devices having Sun SPARC server, an HP Alpha server, an IBM s/390 mainframe on the big iron side to a lightweight ARM Cortex-powered netbook or a Marvell Orion-powered HP Media Vault mv2120 storage device. It is handy whether you are going to upgrade your servers.

19. What is a Debian live install image?

A live install image comes with a Debian system that can be booted without modifying any files present on the hard drive and allowing you to install Debian using the image’s content.

20. What live image is suitable for you?

Consider the following points that will let you decide:

• One can get the live images in various options, allowing you to choose any desktop environment.
• Use the images only for the two most popular architectures, 32-bit PC (i386) and 64-bit PC (amd64).
• The size of every image is much smaller than the complete set of DVD images.
• The images do not come with the support for a complete set of language packages.

21. Is Debian compatible with a 32-bit operating system?

Using a 32-bit operating system, one can efficiently use Debian since a 32-bit system still supports Debian with their latest stable release. We can easily use the Debian 10 Buster, with great support for the 32-bit version until 2024.

22. What is the minimum system requirements for installing Debian?

Here are the basic requirements needed to maintain before installing Debian:

• 512 MB- 2GB RAM
• 10 GB Disk Space
• 1 GHz Processor (Pentium 4 or equivalent)

23. What makes Debian a more preferred distro than others?

Following are some grounds allowing you to compare Debian over others:

• Debian offers a wider range of packaging than other alternatives like Ubuntu, Kubuntu, etc.
• Debian provides the deb packages that help install the deb files hosted on the server.
• Debian offers excellent stability and avoids the breaking of the packages and their dependencies. If using a library that works under Debian development for a particular development, one doesn’t have to worry that your application will break. Also, it provides long release cycles meaning you do not have frequent system updates..
• Debian has a small release size of up to 2 GB, making it easier to handle.

24. How to create an apt repository in Debian?

Here are the steps and run commands for creating an apt repository:

• First, install the dpkg-dev utility:

Then, start creating the repository directory:

Then, start with placing the deb files into the repository directory.
Next, create a file that apt-get update can read:

Then, start adding the required information to your sources.list pointing at your repository:

25. How to create a yum repository in Debian?

You can follow the steps and run the respective commands for creating the yum repository:

First, start installing the createrepo utility:

Then, create the repository directory:

Place the RPM files into the repository directory.
Start creating the repository metadata:

Last, create the repository configuration file:

26. What is the format of a Debian binary package?

The Debian package comes with various executables files, libraries, and required documentation associated with the related programs. The Debian file comes with the extension of .deb. This internal format keeps changing, so one should always use the dpkg-deb for low-level manipulation of the .deb files.

27. What is conffile in Debian?

Debian has a list of configuration files named conffile. This file will not get overwritten by the package management whenever the package is upgraded. Thus, preserving the local values of the file’s content. Also, it is one of the critical features that help enable the in-place package upgrade on the running system.

Run the following command for checking which files are being preserved during the upgrade of the system. In the output of the follwing command, you can even check the status of “conffiles”:

28. What is the Debian preinst script?

This script tends to run before the package to which it belongs. Such a script helps stop the package services that will be upgraded until the installation or upgrade is completed. However, this script will run only after the successful execution of the postinst script.

29. What is the Debian’s postinst script?

To complete the required “oo” package configuration after unpacking the “foo” package from the Debian .deb file, Debian uses a postinst script. After that, this script will run and perform the task like stopping or starting the services after installing or upgrading the new package. Sometimes, you will be asked to provide some input or get a warning regarding the acceptance of the default values. On accepting the default values, the user should remember to go back and re-configure the required packages accordingly.

30. What is a prerm script in Debian?

If there is any daemon service running associated with the package, this script will stop that daemon process. It is usually executed before you remove the file associated with the package.

31. What is the postrm script in Debian?

This script is used to modify the links or any associated files to the “foo” package and remove the files created by the package.

32. What are the various flags available in the package status in Debian?

Here are several flag values that help users perform a specific task for the package:

• unknown: The package is never mentioned as wanted.
• install: It is for installing or upgrading the package.
• remove: It is for removing the package without removing any existing configuration file.
• purge: It is for removing the package along with its configuration files.
• hold: The process of this package will be stopped, which means it will keep the current version intact with the current status, whatever that is.

33. How do you describe a virtual package in Debian?

A virtual package is a name that can be applied to a group of packages that possess similar functionalities. Consider Konqueror and Firefox-ESR programs that are web browsers for satisfying any dependency of a program requiring a web browser running on a system to be useful. They both provide the “virtual package” named www-browser.

34. What is a required package in Debian?

These packages are basic, important, and necessary for the proper and efficient functioning of the system. It comes with all the essential tools for repairing the defects of the system. These packages should not be removed; otherwise, your system will break and use the dpkg package. Having only the required packages makes the system unstable, but they provide enough functionality to the sysadmin to carry out various tasks.

35. What is an important package in Debian?

Such packages are available on Unix-like systems. Such packages only contain the basic infrastructure and do not have Emacs and other large applications available in them.

36. What are the tasks of Debian’s packaging tools?

You can use the packaging tools for the following purposes:

• They help in manipulating and managing the packages or parts of packages.
• They help in administering the local overrides of files within a package.
• They help in providing aid to the developers for the package archive’s construction.
• They help provide the aid for installing the packages to the users who reside on a remote FTP site.

37. How can you install Debian’s source package?

One cannot install the Debian source packages. Instead, one can only unpack those packages in any directory you want to create the binary packages.

Source packages are generally stored on most of the same mirrors from where one can easily and efficiently obtain the binary packages. Once you set up your APT’s sources list, it will help in including the appropriate “deb-src” lines, allowing you to download any source package by running the following command:

38. What is pre-depends in Debian?

There are many cases where dpkf will allow unpacking the archive files of a package without worrying about any dependencies on any other existing file on the system. Unpacking means that the dpkg will help extract the files from the archive files, install them on the system, and place them in the right place. But if the packages come with dependency on any existing file, then dpkg will not start installing the package file until it completes the installation of other packages. Such packages are called pre-depends.

39. What do you mean by a package that is dependent on other packages?

If package “A” depends on package “B,” package B will have to be installed first in order to start the installation of package A.

40. What do you mean by a package that recommends other packages?

If Package A recommends Package B, it means that the user would not use package A without B’s functionality.

41. What do you mean by a package that suggests other packages?

If Package A suggests Package B, it means package B contains the required files related to A’s functionality.

42. What do you mean by a package conflict with other packages?

If Package A conflicts with Package B, it means that Package A will not start operating if B is installed on the system.

43. What do you mean by a package that replaces other packages?

If Package A replaces Package B, it means that when necessary, files installed by B are removed and overwritten by files in A.

44. What do you mean by a package that breaks other packages?

If Package A breaks Package B, it means that both A and B packages cannot be run and configured at the same time within a system. The package management system will not allow one package to install if the other package that tends to break Package A is already installed and configured in the system.

45. What do you mean by a package that provides other packages?

If Package A provides Package B, it means that all of the files and functionality of package B are incorporated into package A. This process provides a way for users with limited disk space to use the specific part of Package A they required.

46. How to check the current directory in Debian?

Use the following command on the command line interface of Debian for checking the current directory in Debian:

47. How can you check the contents of a directory?

Run the following command to list all the contents of a current directory. However, if the current directory is empty, there will be no result on the following command:

48. How can you change the directory in Debian?

Run the following command for changing the working directory:

49. How can you create a directory in Debian?

Run the following command for creating a directory at the present working directory:

50. How can you copy a file from one location to another?

Run the following command with the provided source and destination of the file:

Conclusion

Linux distributions have changed a lot in every possible field like cloud computing platforms, virtualization, and many more. It has gained popularity everywhere. It comes in various distributions, and Debian is one of the most stable and reliable distributions. Debian offers various features and functionalities. It will help you to run and maintain large and complex applications. Among other Linux alternatives, it is one of the best distributions.