LFCS Practice Test 14 — 15 Questions

Question 1

Which two commands can be used to set password expiration policies for a user?

Accepted Answer

passwd. The `passwd` command can set password expiration policies using options like `-x` (maximum days), `-n` (minimum days), `-w` (warning days), and `-i` (inactive days). The `chage` command is the dedicated tool for managing password aging, allowing you to set all expiration parameters interactively or via command-line options. Both commands modify the `/etc/shadow` file to enforce password aging policies.

Answer

usermod

Answer

expiry

Answer

pwconv

Question 2

A security policy requires that all users in the 'webadmin' group should have read and write access to files in /var/www/html. New files created in that directory should automatically be assigned to the 'webadmin' group and have group read/write permissions. Which combination of permissions and group ownership should be set on /var/www/html?

Accepted Answer

chmod g+s /var/www/html; chmod 2775 /var/www/html; chown root:webadmin /var/www/html. Setting the setgid bit (g+s) on /var/www/html ensures that new files inherit the directory's group ('webadmin'), and the 2775 permissions grant group read/write/execute (rwx) while the setgid bit is represented by the leading 2. This combination satisfies the security policy: group ownership inheritance and group read/write access for all new files.

Answer

chmod o+t /var/www/html; chmod 1775 /var/www/html; chown root:webadmin /var/www/html

Answer

chmod g+s /var/www/html; chmod 2755 /var/www/html; chown root:webadmin /var/www/html

Answer

chmod u+s /var/www/html; chown root:webadmin /var/www/html

Question 3

A system administrator needs to configure a static IPv4 address of 192.168.1.100/24 on interface eth0 using NetworkManager. Which command accomplishes this?

Accepted Answer

nmcli con mod eth0 ipv4.addresses 192.168.1.100/24 ipv4.method manual. `nmcli con mod` modifies an existing connection profile, and setting `ipv4.addresses` along with `ipv4.method manual` is the proper way to assign a static IPv4 address in NetworkManager. The `/24` prefix length is correctly specified as part of the address value, and the manual method disables DHCP for IPv4.

Answer

nmcli dev set eth0 ipv4.address 192.168.1.100/24

Answer

nmcli con up eth0 ipv4.address 192.168.1.100/24

Answer

nmcli con add con-name eth0 type ethernet ipv4.address 192.168.1.100/24

Question 4

After adding a new disk and creating an ext4 filesystem on /dev/sdc1 with mke2fs, the administrator added an entry to /etc/fstab to mount it at /data. However, after reboot, the filesystem is not mounted. Which of the following is the most likely cause?

Accepted Answer

The fstab entry uses the device name /dev/sdc1 instead of UUID.. When using device names like /dev/sdc1 in /etc/fstab, the kernel may assign a different device name (e.g., /dev/sdb1) after reboot due to asynchronous device discovery, causing the mount to fail. Using the filesystem's UUID (universally unique identifier) ensures persistent identification regardless of device name changes, which is a best practice for ext4 filesystems created with mke2fs.

Answer

The filesystem superblock was corrupted.

Answer

The filesystem was not formatted correctly.

Answer

The mount point /data does not exist.

Question 5

A system administrator needs to check the current CPU load and memory usage on a Linux server. Which command should be used to display a dynamic, real-time view of running processes and system resource utilization?

Accepted Answer

top. (top) is correct because it provides a dynamic, real-time view of running processes and system resource utilization, including CPU load, memory usage, and process details. It updates continuously by default, making it ideal for monitoring live system performance.

Answer

uptime

Answer

ps aux

Answer

free -h

Question 6

Which TWO commands can be used to display the contents of a text file page by page? (Select two.)

Accepted Answer

more file.txt. The `more` command displays the contents of a text file one screen at a time, pausing after each page and waiting for user input (e.g., pressing the spacebar) to continue. This makes it a classic pager utility for viewing files page by page.

Answer

cat file.txt

Answer

head file.txt

Answer

tail file.txt

Question 7

Refer to the exhibit. The administrator wants to extend the /data filesystem by an additional 10GB. The volume group vg_data has only 1GB of free physical extents. Which action should be taken first?

Accepted Answer

Add /dev/sdc as a physical volume and extend vg_data.. The /data filesystem needs an additional 10GB, but vg_data has only 1GB of free physical extents. To extend the logical volume, the volume group must have sufficient free physical extents. Adding /dev/sdc as a physical volume and extending vg_data increases the pool of physical extents, making the required space available. This is the correct first step because you cannot extend a logical volume beyond the available free extents in its volume group.

Answer

Delete the /backup logical volume to free space.

Answer

Reduce the size of /backup to free space in vg_data.

Answer

Create a new logical volume from the free space in vg_data.

Question 8

A system administrator needs to configure a network bond on a Linux server using NetworkManager. Which TWO steps are required to create a functional bond interface?

Accepted Answer

Use 'nmcli connection add type bond ifname bond0' to create the bond interface.. The two required steps are creating the bond connection and attaching slave interfaces. The bonding kernel module is usually loaded automatically. Setting the bond mode and IP address can be done later, and the slave interfaces do not need to be down.

Answer

Set the bond mode to 'balance-rr' in the connection profile.

Answer

Load the bonding kernel module using 'modprobe bonding'.

Answer

Ensure that the slave interfaces are down before adding them to the bond.

Question 9

A system administrator needs to find all files in /var/log that have been modified in the last 7 days. Which command accomplishes this?

Accepted Answer

find /var/log -type f -mtime -7. The `find` command with `-mtime -7` searches for files whose modification time (content change) is less than 7 days ago, which matches the requirement of 'modified in the last 7 days'. The `-type f` restricts the search to regular files, and `/var/log` is the target directory.

Answer

find /var/log -type f -atime -7

Answer

find /var/log -type f -ctime -7

Answer

find /var/log -type f -mtime +7

Question 10

Which TWO commands can be used to check the status of the sshd service on a system using systemd?

Accepted Answer

systemctl is-active sshd. `systemctl is-active sshd` directly queries systemd to report whether the sshd service is currently in an active (running) state, returning a simple exit code and text output (e.g., 'active' or 'inactive'). Option E is correct because `systemctl status sshd` provides a comprehensive view of the service's current state, including whether it is active, its PID, recent log entries, and cgroup details, making it a standard command for checking service health on systemd-based systems.

Answer

systemctl list-units --type=service

Answer

systemctl is-enabled sshd

Answer

systemctl cat sshd

Question 11

Which THREE of the following are valid systemd unit types?

Accepted Answer

target. 'target' is a standard systemd unit type used to group other units together, similar to runlevels in SysVinit. Targets are defined in .target files and are essential for defining synchronization points during system boot or service state transitions.

Answer

notification

Answer

startup

Question 12

An administrator needs to schedule a cron job that runs a script every day at 3:00 AM, but the system is in a different time zone (UTC) than the administrator's local time (EST). The administrator wants the job to run at 3:00 AM local time regardless of system time zone changes. What is the best approach?

Accepted Answer

Use the CRON_TZ variable in the crontab file to specify EST and schedule at 3:00 AM. The CRON_TZ variable, when set in a crontab file, allows you to specify a time zone for the cron daemon to interpret the schedule entries. This ensures the job runs at 3:00 AM EST regardless of the system's default time zone (UTC), and it persists even if the system time zone changes, as cron uses the variable for scheduling.

Answer

Change the system time zone to EST and set the cron job to run at 3:00 AM

Answer

Set the TZ environment variable in the crontab file before the job definition

Answer

Calculate the UTC equivalent (8:00 AM UTC) and schedule the job at that time

Question 13

An admin notices a PV in a VG has failed. The VG is still accessible with redundancy. Which command sequence should be used to replace the faulty PV with a new one (/dev/sde) while the VG is active and without data loss?

Accepted Answer

pvcreate /dev/sde; vgextend VG_name /dev/sde; pvmove /dev/sdb /dev/sde; vgreduce VG_name /dev/sdb. It first creates the new PV on /dev/sde, extends the VG to include it, then uses pvmove to migrate data from the failing PV (/dev/sdb) to the new PV while the VG is active, and finally removes the faulty PV from the VG with vgreduce. This sequence ensures no data loss and maintains VG availability throughout the replacement process.

Answer

pvcreate /dev/sde; vgreduce VG_name /dev/sdb; vgextend VG_name /dev/sde; pvmove /dev/sdb

Answer

pvcreate /dev/sde; pvmove /dev/sdb /dev/sde; vgextend VG_name /dev/sde; vgreduce VG_name /dev/sdb

Answer

vgreduce --removemissing VG_name; pvcreate /dev/sde; vgextend VG_name /dev/sde; pvmove /dev/sde

Question 14

Which command can be used to display the UUID of a filesystem on /dev/sdb1?

Accepted Answer

blkid /dev/sdb1. The blkid command is specifically designed to locate and print block device attributes, including the UUID and filesystem type. When run against a device like /dev/sdb1, it queries the kernel's device mapper and reads the filesystem superblock to extract the universally unique identifier (UUID). This is the most direct and reliable method for displaying a filesystem's UUID.

Answer

tune2fs -l /dev/sdb1

Answer

df -h /dev/sdb1

Answer

lsblk /dev/sdb1

Question 15

A system administrator monitors a server that periodically becomes unresponsive for a few seconds. Investigation reveals that the kernel OOM killer is being invoked, but standard memory usage monitoring tools like 'free' and 'top' show less than 50% memory usage. The server runs a web server and a database. Which of the following is the most likely cause and diagnostic step?

Accepted Answer

The kernel is using a large amount of memory for slab caches. Use 'slabtop' to examine kernel memory allocations.. The kernel OOM killer can be triggered by high slab cache usage, which is memory allocated for kernel data structures like inode and dentry caches. Standard tools like 'free' and 'top' may show low overall memory usage because they report only user-space memory, while slab caches are accounted separately. Using 'slabtop' allows the administrator to identify which kernel slab caches are consuming excessive memory, often due to a large number of small files or heavy filesystem metadata operations.

Answer

The server is experiencing a fork bomb. Use 'ps -ef | wc -l' to count processes.

Answer

The database is using swap space excessively. Use 'swapon -s' to check swap usage.

Answer

The web server is leaking file descriptors. Use 'lsof -n' to check open files.