UNIX Commands Interview Questions and Answers
UNIX commands are text-based instructions used to perform specific operations on a UNIX-based operating system. Some of the more popular examples include ls, cd, pwd, cp, mv, rm and even grep (search files for patterns) or echo (display text on screen).
These commands, typically entered at a terminal or command prompt, enable you to navigate your file system, manage files and directories, search information and perform system administration duties, these are some interview questions for unix commands.
1. What is Unix?
Unix is a simple and widely used operating system in enterprise applications, offering various tasks.
2. What is the Unix operating system?
Unix is an operating system similar to Windows and iOS and focuses on its fundamental aspects, such as architecture, advantages, disadvantages, and features.
3. What are the four components of Unix architecture?
The four components of Unix architecture are the outer core, the shell, the kernel, and the actual hardware.
4. What is the kernel in Unix architecture?
The kernel connects the hardware and the shell program in Unix architecture.
5. How does Unix architecture manage communication between the hardware and kernel?
The protocol in Unix architecture manages communication between the hardware and the kernel.
6. What are the similarities between Unix and Linux operating systems?
Unix and Linux are two operating systems with similar appearance and functionality, both are called Flavors of Unix or a Unix clone and have their own individual features.
7.What are the unique features of the Unix operating system?
Unix has a wide range of browsers, such as Chrome, Firefox, Opera, CMonkey, MacsCon, JNU, iScat, Thar, Pelmoon, and Doodle; it also has unique features and limitations compared to other operating systems like Linux and Windows.
8. What is Unix used for?
Unix can be used for minor calculations, such as calculating simple two-number sums or implementing complex programs to optimise existing ones.
9. How is Unix used for automation purposes?
Linux or Unix are used widely for automation purposes, such as Hadoop, which requires the HDFS file of the command line operating system, which works on the underlying Unix.
10. How do you display a list of the current working directory/files in Unix?
To show a list of the current working directory or files in Unix, use Python to list all files and the minus l option to provide a long listing, for example, ls minus l a will show all directives and hidden files, and the minus l option provides additional information for hidden files.
11. What are the advantages of Unix?
Unix has several advantages, including multitasking, access controlling secrets, and a powerful and unified file system.
12. What are Unix’s disadvantages?
The first disadvantage of Unix is its incompatible disk format, which can cause issues with disformatting and has a less appealing interface; additionally, installing software in Unix may be challenging due to software incompatibility.
13. What is the main component of the UNIX operating system?
The main component of the UNIX operating system is the shell, which provides commands to the operating system and translates them into a machine-readable language understood by the kernel.
14. What is the kernel’s role in the UNIX operating system?
The kernel is the operating system that runs on the hardware and is responsible for memory management, task scheduling, and file management.
15. What is the purpose of the user space in the UNIX architecture?
The user space in the UNIX architecture represents the space from which the user interacts with the hardware.
16. What is the role of the hardware in the UNIX architecture?
The hardware is the core part of the UNIX operating system, installed on top of the hardware.
17. What is the purpose of the shell command in the UNIX architecture?
The shell command in the UNIX architecture provides access to various commands and allows applications to interact with the hardware using the kernel.
18. What is the purpose of the terminal options?
The terminal options include settings such as the terminal name, font colour, background colour, cursor shape, and text appearance, and these options can be modified to customise the terminal’s appearance and functionality.
19. How do you increase the terminal size?
To increase the terminal size, go to the edit and profile preferences; in profile preferences, select the General tab and change the terminal size to your desired value; also, change the terminal size later on if you want.
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20. What are the different options for customising the theme in the UNIX terminal?
In the UNIX terminal, users can customise the theme by selecting a default theme (black and grey background) or using a custom scheme, which can be changed to any desired color.
Users can also choose between scrolling options such as scroll on output, scroll on keystroke, limit scroll, and fake scroll speed.
21. What encoding choices are available in the UNIX terminal?
In the UNIX terminal, users can choose the encoding; UTF-8 encoding is the most commonly used encoding, providing the most characters; users can also select other encodings based on their preferences.
22. What are the basic commands used in the UNIX environment?
Some basic commands used in the UNIX environment include the password, calendar, clear, and ls minus l commands; the password command allows users to change their current password, the calendar command provides information about the current date, month, and year, the clear command clears the screen.
The ls minus l command lists all files and directories in the current folder or directory.
23. How do you create a directory in Unix?
To create a directory in Unix, use the command mkdir and the directory name, to view the directory, use ls (list files and directories) and the directory name.
To create multiple directories, use mkdir and give the multiple directory names, the naming convention will change, but you can provide any name for the directory.
24. what is the difference between a block spatial file, a block input or output device file, and a character spatial file?
Block spatial files are input or output device files, such as a physical hard drive, and character spatial files are raw input or output device files, such as a physical hard drive.
25. What commands are available for listing files in Unix environments?
The command ls (list files) or ls minus l (minus l) lists all files in a directory and provides additional information about the file type, permissions, owner, group, file size, date, and directory name.
26. What are meta characters in Unix, and what do they do?
Meta characters in Unix are asterisk, star, and question mark symbols; the asterisk and question mark symbols give 0 or more characters, while the file question mark gives single characters; these symbols are useful for managing files in the Unix environment.
27. How can you list all files starting with a specific character in Unix?
To list all files starting with a specific character in Unix, use the command ls minus the first character followed by the remaining characters; for example, to record all files beginning with the character p, use ls minus p as a rig.
28. How can you list files where you don’t know the first character but know the remaining characters in Unix?
To list files for which you don’t know the first character but know the remaining characters in Unix, use the command ls minus l followed by the remaining characters; for example, to list all files whose file names start with the letter p, use ls minus l test.txt.
29. What is the difference between single and double dots in Unix?
In Unix, a single dot represents the current directory, in contrast, a double dot represents the parent directory; the dot indicates the current directory, and the double dot indicates the parent directory for this by its current location, which is again hidden.
30. How can you view hidden files in Unix?
To view hidden files in Unix, use the option hi one a followed by the ls command. This will list all the files hidden in your directory; if you want to list files not listed earlier, use the option ls minus a followed by ls minus a.
31. How do you create an edit file in Vi editor?
To create an edit file in the Vi editor, use the command “vi” followed by the file name and any extension, and the cursor will move to the top, allowing you to type content in the file.
32. What is the pwd command in Unix?
The pwd command in Unix is used to display the current working directory.
33. What is the word count command in Unix?
The word count command in Unix provides information about the total number of lines, words, and characters in a file, it can count the words in all files and copy, move, and delete cursors, however, it does not consider hidden files.
34. How do you delete a file in Unix?
To delete a file in Unix, use the “rm”(remove files and directories) command followed by the file name.
35. What are standard input streams in Unix?
Standard input streams in Unix are input and output streams, the standard input stream has an associated file descriptor of 0, the expected output stream is related to a file descriptor of 1, and the standard error stream is associated with file descriptor 2.
36. How does Unix handle file copying, renaming, and deletion?
To copy, rename, or delete files in Unix, use the “cp”, “mv”, or “rm” commands, respectively.
37. What do the dot and double dot represent in UNIX?
A single dot represents the current directory in UNIX, while a double dot represents the parent directory.
38. What is the standard output stream in Unix?
The standard output stream in Unix has an associated file descriptor of 1 and is represented as SDD OUT; the Unix program will write all output to the standard output.
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To create a new file in Vi editor and list all files, use the command “ls minus l” to print the file’s owner, the owner of this file is MDM, a 36-byte character file. To insert content using Escape and I, use “ls minus l” and print the file owner.
40. What is the cp command in Unix?
The cp command in Unix copies, renames, and deletes files.
41. What is the mv command in Unix?
mv (move files and directories) command in Unix moves a file from one location to another.
42. How do you remove or delete a directory in Unix?
To remove or delete a directory in Unix, ensure it is empty, meaning there are no files or subdirectories, use the rm command to remove multiple directories and the iR command to remove one directory, to test if the directory contains a folder or files, use the rmdir command.
43. What is the ls command in Unix?
The ls (list files and directories)command in Unix lists all files starting with a p, if you want to remove a specific file, use rm p or test.txt.
44. What is the standard input stream in Unix?
The standard input stream in Unix has an associated file descriptor of 0 and is represented as sddin, the Unix program will read the default input from the standard input.
45. What is the standard error stream in Unix?
The standard error stream in Unix has an associated file descriptor of 2 and is represented a Sdderr, the Unix program will write all error messages to the standard error stream.
46. What is the cd command in Unix?
cd command in Unix is used to change to a different directory.
47. How does one count words in a Unix file?
To count words in a file in Unix, use the “wc” command and specify the file name.
48. What is the difference between Unix’s home and root directory?
A home directory is directly accessible when a user logs into the system; it contains files specific to that user,on the other hand, the root directory has all files and subdirectories on the system and is accessible only by the root user.
49. What is a directory in a Unix system?
A directory in a Unix system is a file that stores file names, related information, and all files, including particular files and subdirectories; the directory tree is maintained in the Unix system for every folder, and using these commands allows you to navigate to different directories and users.
50. What are the two concepts in Unix regarding directories?
The two concepts in Unix regarding directories are absolute path and relative path. Absolute path refers to a directory hierarchy with a forward slash at the top, and the position of any file within the hierarchy is discarded by the path name; a relative path is a path name relative to the current working directory.
51. How do you use an absolute path to navigate to a directory?
To navigate a directory using an absolute path, you must use the forward slash and give the whole path from your root directory, and you can use this one to go to the hub directory or the relative path to get the path of the current location, you can use the pwd command, which you give as the path of your current location.
52. When the ls command is used in Unix environments, what information is provided by the first column of the output?
This section provides information about the file type and permissions given on that file, whether it is a directory or file, the number of memory blocks taken by the file or directory, the owner of that file, and the group of owners.
53. What is the rm command in Unix?
rm (remove files and directories) command in Unix is used to delete a file from the system.
54. How does one modify the directory in Unix?
To change the directory in Unix, use the cd command, two dots represent the parent directory, while one represents the current one, a single dot represents the current working directory, and a double dot represents the directive one level above the active directory.
The file name dot represents the current working directory.
55. What interfaces are built on top of Unix?
Several interfaces are built on top of Unix, such as application servers like Web Spear, WebLogic, and JBoss, which generate lots of files and processing power when executed on Unix.
56. How do you copy a file from another subdirectory to the current directory in Unix?
To copy a file from another subdirectory to the current directory in Unix, use the command pwd (print working directory), this command will copy the file from the other subdirectory to the current directory, the dot means the current directory.
This drill aims to help you understand the directory structure and basic commands such as creating, renaming, or deleting directories.
Choose the correct answer for your better understanding of UNIX Commands
1. What is the operating system that is similar to Windows and iOS?
Mac
Linux
Answer: Unix
Android
2. What is the shell in Unix?
Answer: Programming layer where programs can be written
Kernel
Application
Outer core
3. What is the kernel in Unix?
Shell
Application
Answer: Kernel
Outer core
4. What is the purpose of Unix operating system?
Answer: Automate and develop enterprise applications
Access and test internet and application within Windows operating system
Perform other functions
Perform all of the above
5. To list all the files present in a current directory, use the command:
Answer: ls (list files)
cd (change directory)
mkdir (create directory)
rm (remove file).
UNIX commands are text-based tools used to interact and manipulate files and directories on Unix-based operating systems, often by advanced users and administrators performing advanced tasks with precise control and precision.
As with all tools used for tasks that involve more precision or control than you are familiar with it is critical that they be treated responsibly by both themselves as users and by administrators when performing advanced tasks with precision or control.
Always ensure to use these commands with care, keeping in mind truth and utility.
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