Practice for the LPI Linux Essentials exam with 13 exam-style practice questions, instant answer reveals, and concise explanations of every correct answer. Topics include: What command would you use to get comprehensive documentation about any command in Linux?. Follow @CertPunch and visit certpunch.com for more certification practice exams and study content.
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What you will practice
- What command would you use to get comprehensive documentation about any command in Linux?
- What command should be used to display the permissions for every file in the current directory?
- Which software handles the installation and removal of software on Debian and Ubuntu?
- What command would you use to create a symbolic link in Linux?
- Where are the passwords stored for users on a Linux system?
- Which UID is usually used to represent the root user on a Linux system?
Answers and explanations
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Q1. What command would you use to get comprehensive documentation about any command in Linux?
Answer: C. man command
The man command opens the system manual pages, providing comprehensive documentation for commands. While other commands like help exist, man is the standard utility tested for viewing full documentation.
Q2. What command should be used to display the permissions for every file in the current directory?
Answer: A. ls -la
The ls command with the dash l and dash a flags displays permissions for all files. The dash a flag ensures hidden files are shown, while the dash l flag provides the detailed permission strings.
Q3. Which software handles the installation and removal of software on Debian and Ubuntu?
Answer: A. apt
APT is the package manager used to install and remove software on Debian and Ubuntu systems. RPM and YUM are used by Red Hat based distributions, making them incorrect for Debian.
Q4. What command would you use to create a symbolic link in Linux?
Answer: B. ln -s
The ln -s command creates a symbolic link, which acts as a shortcut pointing to the original file's path. Avoid the standard ln command without the dash s flag, because that creates a hard link rather than a soft link.
Q5. Where are the passwords stored for users on a Linux system?
Answer: B. /etc/shadow
The /etc/shadow file stores the hashed passwords and password aging data for user accounts. The /etc/passwd file is a common distractor, but it is world-readable and only stores the placeholder character, not the actual password hash.
Q6. Which UID is usually used to represent the root user on a Linux system?
Answer: A. 0
The root superuser account is always assigned the user ID of zero, granting complete administrative privileges. Normal user accounts typically start at one thousand or higher, while system processes use lower identifier numbers.
Q7. How would you represent rwxr-xr– in octal notation?
Answer: A. 754
The permissions rwxr-xr– convert to the octal value 754 by adding the numeric values for each triad. Add four for read, two for write, and one for execute, mapping the sums sequentially to the owner, group, and others.
Q8. Which of the following is the dmesg command used for?
Answer: B. To show the kernel log messages
The dmesg command reads and prints the kernel ring buffer, which contains hardware initialization and driver messages. Do not confuse this with syslog, which aggregates broader system and daemon messages from various background services.
Q9. Which of the following software packages is a mail server?
Answer: C. Postfix
Postfix is a mail transfer agent responsible for routing and delivering email over a network. Distractors like Thunderbird and Apache fail because they are an email client and a web server, respectively.
Q10. Which of the following commands creates an archive file work.tar from the contents of the directory ./work/?
Answer: B. tar -cf work.tar ./work/
The -c option creates a new archive, while -f specifies the output file. Watch for the correct order, as tar requires the exact filename immediately following the -f flag.
Q11. Which command will display the last line of the file document.txt?
Answer: B. tail -n 1 document.txt
The tail command displays the end of a file, and -n 1 specifies exactly one line. A bare tail defaults to ten lines, and last shows login history, not file text.
Q12. Which of the following commands is used to extract files from a zip archive?
Answer: C. unzip
The unzip command extracts files from a ZIP archive by default. Remember that tar handles uncompressed or natively compressed tarballs, making it the wrong tool for ZIP files.
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