010-160 The Linux Operating System — 10 Questions

Question 1

You are configuring a Linux server and need to determine which hard drive partition is currently mounted as the root filesystem. Which file should you inspect?

Accepted Answer

/etc/fstab. The /etc/fstab file is the system's static filesystem table, which lists all filesystems and their mount points, including the root filesystem. By inspecting /etc/fstab, you can see which partition is designated as the root filesystem (mounted at '/'). This is the correct file to check for the configured root partition, though note that the actual runtime mount may differ if the system was booted with different parameters or if the filesystem was remounted.

Answer

/var/log/dmesg

Answer

/etc/passwd

Answer

/proc/partitions

Question 2

A user reports that they cannot save files to their home directory. You find that the disk is not full. What is the most likely cause related to hardware-based limitations?

Accepted Answer

The partition has run out of inodes.. Even when disk space is free, a filesystem can run out of inodes — the fixed-size data structures that track each file's metadata. Once all inodes are consumed, no new files can be created, producing 'No space left on device' errors despite available blocks. This is a hardware/filesystem-level limitation independent of raw capacity. The other options relate to memory, CPU, or firmware, which wouldn't specifically block file creation while space remains.

Answer

The RAM is corrupted.

Answer

The CPU temperature is too high.

Answer

The BIOS settings are incorrect.

Question 3

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 is the standard Linux configuration file that specifies the DNS servers (nameservers) the system uses to resolve domain names into IP addresses. Since the server can ping the gateway but cannot ping the website by IP, the issue is likely name resolution, not routing. Checking /etc/resolv.conf ensures that valid DNS server entries are present and reachable. Without correct nameserver entries, the system cannot translate domain names to IPs, causing ping to fail even if the network path is fine.

Answer

/etc/network/interfaces

Answer

/etc/sysconfig/network

Answer

/etc/hosts

Question 4

You are configuring a static IP address on a Debian-based server. Which file must be modified to make this change persistent across reboots?

Accepted Answer

/etc/network/interfaces. On Debian-based systems, persistent network configuration is stored in /etc/network/interfaces (or /etc/network/interfaces.d/), where you define the interface with iface eth0 inet static, address, netmask, and gateway. Editing this file and restarting networking (or rebooting) makes the static IP persist. The other files serve different purposes and do not configure interface IP addressing.

Answer

/etc/hosts

Answer

/etc/sysconfig/network-scripts/ifcfg-eth0

Answer

/etc/resolve.conf

Question 5

A user is complaining that their application runs slowly. You suspect the system is swapping excessively. Which command shows the current usage of swap space?

Accepted Answer

swapon -s. The free command displays total, used, and free swap space.

Answer

fdisk -l

Answer

vmstat

Answer

mount

Question 6

Which command is used to safely shut down the system immediately?

Accepted Answer

poweroff. The shutdown -h now command sends a signal to the init system to power off the machine.

Answer

reboot

Answer

exit

Question 7

You want to view the kernel's boot messages to check for driver initialization errors. Which command is most appropriate?

Accepted Answer

journalctl -b. dmesg reads the kernel ring buffer, which holds boot-time messages.

Answer

cat /var/log/auth.log

Answer

lsmod

Answer

modprobe

Question 8

You have modified a configuration file for a network service. Which command is best practice to test the configuration syntax before restarting the service?

Accepted Answer

apache2ctl -t. apache2ctl -t (equivalently 'apachectl configtest' or 'httpd -t') parses the Apache configuration files and reports syntax errors without restarting or reloading the service. This is the documented best practice for validating httpd.conf and included vhost files before applying changes, letting you catch typos and directive errors safely. It is the only option that actually tests configuration syntax rather than changing service state.

Answer

systemctl reload

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systemctl status

Answer

service name test

Question 9

A user on a Linux workstation wants to know which shell is currently active for their login session. Which command should they run?

Accepted Answer

echo $SHELL. The $SHELL environment variable is set at login and contains the path to the user's default shell. Displaying it with echo provides a direct, reliable answer. Other commands either list all processes, inspect account databases, or show kernel details, none of which identify the shell currently in use for the session.

Answer

uname -a

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cat /etc/passwd

Answer

ps -ef | grep bash

Question 10

A Linux user wants to change the permissions of a file named report.txt so that the owner can read and write, the group can read, and others have no access. The current permissions are rw-r--r--. Which command will set the permissions to rw-r-----?

Accepted Answer

chmod 640 report.txt. The desired permissions rw-r----- correspond to the octal digits 6 (owner: read+write), 4 (group: read), and 0 (others: none). The command chmod 640 report.txt sets these exact permissions. The other numeric modes either grant others read access or remove group read access, and while the symbolic mode can achieve the same result, the numeric mode is the standard and unambiguous answer expected in this context.

Answer

chmod u=rw,g=r,o= report.txt

Answer

chmod 644 report.txt

Answer

chmod 604 report.txt