010-160 Hard Questions — 25 Difficult Questions

Question 1

Which command displays the first 5 lines of a file?

Accepted Answer

head -5 file. -n 5 specifies the number of lines for the head utility.

Answer

tail -n 5 file

Answer

cat -n 5 file

Question 2

Which command would you use to list files in long format, sorted by modification time, with the newest files appearing first?

Accepted Answer

ls -ltr. The -l (long), -t (time), and -r (reverse) flags together achieve this.

Answer

ls -lt

Answer

ls -lr

Answer

ls -Rlt

Question 3

You are trying to find the location of a binary file, specifically the 'ls' command. Which command is best suited for this?

Accepted Answer

which. The 'which' command finds the location of an executable in the user's PATH.

Answer

find

Answer

locate

Answer

whereis

Question 4

Which TWO statements regarding the 'umask' command are correct?

Accepted Answer

It sets default permissions for new files.. Umask defines default permissions for new files and directories, and it acts as a mask by subtracting bits from the maximum possible permission.

Answer

It can only be set by root.

Answer

It is stored in /etc/shadow.

Answer

It applies to existing files immediately.

Question 5

Which THREE of the following are typical elements included in a standard Linux distribution package?

Accepted Answer

Package Manager. A distribution consists of the kernel, a package manager, and a set of libraries and base applications.

Answer

Proprietary BIOS firmware

Answer

Hardware warranty certificate

Question 6

You want to delete a user account named 'baduser' and also remove their home directory. Which command is correct?

Accepted Answer

userdel -r baduser. The '-r' flag with 'userdel' removes the user's home directory and mail spool.

Answer

deluser --remove baduser

Answer

userdel -f baduser

Answer

rm -rf /home/baduser && userdel baduser

Question 7

When evaluating Linux distributions, what distinguishes a 'rolling release' distribution from a 'fixed release' distribution?

Accepted Answer

Rolling releases provide continuous updates, while fixed releases use a versioned lifecycle.. Rolling releases receive updates continuously, providing the latest software, while fixed releases have scheduled versions with stable software packages.

Answer

Fixed releases are only available for server environments.

Answer

Rolling releases require a complete wipe and reinstall for every update.

Answer

Rolling releases are always more secure than fixed releases.

Question 8

An administrator is comparing package management systems. Which tool is primarily used on RHEL-based distributions for resolving dependencies and downloading packages?

Accepted Answer

DNF. DNF (Dandified YUM) is the standard package manager for modern RHEL-based distributions, succeeding YUM.

Answer

Pacman

Answer

Portage

Answer

APT

Question 9

You need to see the last 20 lines of a file named 'access.log'. Which command is the most appropriate?

Accepted Answer

tail -n 20 access.log. The tail command with the -n option allows specifying the number of lines to display from the end of the file.

Answer

cat -n 20 access.log

Answer

less -n 20 access.log

Answer

head -n 20 access.log

Question 10

A developer is writing an application that performs heavy system-level calls. Why would they choose to use Linux for this development?

Accepted Answer

Because the source code is transparent, allowing for deep optimization and debugging.. Linux is open source, allowing developers to see exactly how system calls are handled by the kernel, which is vital for performance tuning.

Answer

Because it is the only operating system that supports multi-threading.

Answer

Because Linux has a graphical user interface that is mandatory for all applications.

Answer

Because Linux only runs on x86 hardware.

Question 11

You are troubleshooting a network issue where a Linux server cannot reach an external website. The ping command to the gateway succeeds, but pinging the website IP fails. Which configuration file should you check to ensure the server can resolve domain names?

Accepted Answer

/etc/resolv.conf. The /etc/resolv.conf file contains DNS server addresses required for domain name resolution.

Answer

/etc/network/interfaces

Answer

/etc/sysconfig/network

Answer

/etc/hosts

Question 12

Which TWO of the following locations or methods are commonly used to define where a user's home directory is located?

Accepted Answer

The useradd -d flag. The home directory is set in /etc/passwd or during the useradd command via the -d flag.

Answer

The /etc/profile file

Answer

The /etc/group file

Answer

The /etc/shadow file

Question 13

What is the result of running 'chmod 000 secret.txt'?

Accepted Answer

No user can access it (except root).. 000 removes all permissions for owner, group, and others. The file is inaccessible to everyone except root.

Answer

The file becomes read-only for root.

Answer

Only the owner can access it.

Answer

The file is deleted.

Question 14

Which TWO of the following are valid ways to create a directory?

Accepted Answer

install -d. mkdir is the standard command, and install with -d is a less common but valid method.

Answer

touch

Answer

ln

Answer

cp -d

Question 15

You are managing a directory shared by a project team. You want all files created in this directory to automatically belong to the 'developers' group, regardless of the user's primary group. Which command achieves this?

Accepted Answer

chmod g+s /data. Setting the setgid bit (chmod g+s) on a directory ensures that new files created within inherit the group ownership of the directory.

Answer

usermod -aG developers

Answer

chgrp developers /data

Answer

chmod 1777 /data

Question 16

You notice a file has permissions listed as '-rwsr-xr-x'. What does the 's' in the owner's position indicate?

Accepted Answer

The file is a setuid binary.. The 's' in the owner's field indicates the setuid bit is set, meaning the file runs with the privileges of the file owner rather than the user running it.

Answer

The file is a setgid binary.

Answer

The file is immutable.

Answer

The file is a sticky directory.

Question 17

Why do many enterprise Linux distributions choose to delay the inclusion of the absolute latest kernel version?

Accepted Answer

Because they prioritize stability and extensive testing to ensure production uptime.. Enterprise distributions prioritize stability and exhaustive testing over having the absolute newest features.

Answer

Because the latest kernel is always incompatible with proprietary software.

Answer

Because they are legally required to wait 12 months.

Answer

Because they lack the technical staff to compile new kernels.

Question 18

Which THREE of the following are special permission bits in Linux?

Accepted Answer

Sticky bit. Setuid, setgid, and the sticky bit are the three special permission bits.

Answer

Immutable bit

Answer

Append-only bit

Question 19

You are setting up a local network and need to verify the path traffic takes to reach a remote host. Which command should you use?

Accepted Answer

traceroute. The traceroute command displays the path and latency of each hop to a destination.

Answer

nmap

Answer

ping

Answer

dig

Question 20

You want to combine the output of 'cat file1' and 'cat file2' and count the total number of lines in the result. Which pipe sequence is correct?

Accepted Answer

wc -l file1 file2. Piping joins commands; 'cat' sends data to 'wc -l' to count lines.

Answer

cat file1 + file2 | wc -l

Answer

cat file1 file2 > wc -l

Answer

cat file1 | cat file2 | wc -l