EX200 Practice Test 5 — 25 Questions

Question 1

An administrator needs to schedule a script to run every Monday, Wednesday, and Friday at 2:30 PM. Which cron expression should be used?

Accepted Answer

30 14 * * 1,3,5. Cron uses five fields (minute, hour, day-of-month, month, day-of-week). 2:30 PM is 14:30 in 24-hour format, so minute=30 and hour=14. The day-of-week field uses 0-7 (0 and 7 = Sunday), with Monday=1, Wednesday=3, Friday=5. The asterisks for day-of-month and month mean 'every day' and 'every month', so the expression `30 14 * * 1,3,5` runs the script at 2:30 PM on Monday, Wednesday, and Friday.

Answer

30 14 * * 1-5

Answer

14 30 * * 1,3,5

Answer

30 14 * * 0,2,4

Question 2

A systems administrator installs a custom hardware device driver kernel module named 'mydevice' on a RHEL 9 system. The module is built and placed in /lib/modules/$(uname -r)/extra/. The administrator loads it manually with modprobe mydevice and it works. However, after a system reboot, the module is not loaded. The administrator checks that the device is present at boot time. Which step should be taken to ensure the module loads automatically at boot?

Accepted Answer

Run 'echo mydevice > /etc/modules-load.d/mydevice.conf'. Writing the module name to a file in /etc/modules-load.d/ ensures systemd loads the module automatically at boot. The modules-load.d mechanism is the standard RHEL 9 method for specifying kernel modules to be loaded early in the boot process, before the root filesystem is fully available.

Answer

Add the line 'install mydevice /sbin/modprobe --ignore-install mydevice' to /etc/modprobe.d/load.conf

Answer

Rebuild the initramfs with 'dracut --force --add mydevice'

Answer

Add the line 'load mydevice' to /etc/rc.local and ensure rc.local is executable.

Question 3

Which TWO commands can be used to add a user to a secondary group without removing existing supplementary group memberships? (Choose exactly 2)

Accepted Answer

usermod -aG group user. `usermod -aG` appends the user to the specified supplementary group(s) without affecting any existing supplementary group memberships. The `-a` flag (append) must be used with `-G` to avoid overwriting the current list of supplementary groups. This is the standard method in Red Hat Enterprise Linux for adding a user to an additional group while preserving all other group memberships.

Answer

usermod -AG group user

Answer

adduser user group

Answer

groupadd -a user group

Question 4

A developer wrote a shell script that is intended to back up log files by copying all .log files from /var/log/myapp to /backup/logs. The script runs daily via cron but the backup folder is empty. The script contains the following line: `cp /var/log/myapp/*.log /backup/logs/`. What is the most likely reason the backup fails?

Accepted Answer

No .log files exist in /var/log/myapp at the time of script execution, causing the glob to match nothing.. The glob pattern `*.log` in the `cp` command is expanded by the shell at the time the script runs. If no `.log` files exist in `/var/log/myapp` when the cron job executes, the shell passes the literal string `*.log` to `cp`, which then fails with a 'No such file or directory' error (or, depending on shell settings, may silently do nothing). This is a common issue when log rotation or cleanup removes files before the backup runs.

Answer

The PATH variable in cron is not set, so cp cannot be found.

Answer

The script does not have execute permission for the user running cron.

Answer

The cron job is not enabled because the crontab syntax is incorrect.

Question 5

The administrator attempts to run 'xfs_growfs /dev/vg00/lvol1' but receives an error. What is the most likely cause?

Accepted Answer

The logical volume is not mounted. The `xfs_growfs` command requires the XFS filesystem to be mounted in order to resize it. If the logical volume `/dev/vg00/lvol1` is not mounted, the kernel cannot access the filesystem's superblock and allocation group information, causing the command to fail with an error such as 'XFS filesystem not mounted' or 'No such file or directory'.

Answer

The file system is not XFS

Answer

Unmet dependencies

Answer

The volume group is full

Question 6

An administrator wants to add 20GB of additional space to the root filesystem. The volume group vg01 has no free extents. Which action should be taken first?

Accepted Answer

Attach a new disk, create a physical volume on it, add it to vg01 with vgextend, then extend vg01-root. To extend the root filesystem when the volume group has no free extents, you must first add a new physical volume to the volume group. This involves attaching a new disk, creating a physical volume on it with `pvcreate`, adding it to vg01 with `vgextend`, and then using `lvextend` followed by `resize2fs` (or `xfs_growfs` for XFS) to extend the logical volume and filesystem. This sequence ensures the volume group has available extents before extending the logical volume.

Answer

Shrink the logical volume vg01-data and then extend vg01-root

Answer

Run vgextend vg01 /dev/sdc (assuming /dev/sdc is a new disk) but this command requires the PV to be created first

Answer

Use lvextend to extend the root logical volume into the free space of sdb1

Question 7

Refer to the exhibit. An administrator wants to create an LVM logical volume using /dev/sdb3. What is the first step to complete this task?

Accepted Answer

Create a logical volume with lvcreate -L 10G -n lv01 vg01. Based on the exhibit, /dev/sdb3 is already initialized as a physical volume and belongs to a volume group. Therefore, the first step to create a logical volume is to use lvcreate directly, as the PV and VG are already in place. Option B is incorrect because pvcreate is not needed when the partition is already a PV.

Answer

Format the partition with mkfs.ext4 /dev/sdb3

Answer

Create a physical volume with pvcreate /dev/sdb3

Answer

Create a volume group with vgcreate vg01 /dev/sdb3

Question 8

A RHEL 9 system has a second disk /dev/sdb that needs to be partitioned with a single partition using all space, formatted with XFS, and mounted persistently at /data. The administrator uses fdisk to create the partition /dev/sdb1. Which filesystem creation command should be used?

Accepted Answer

mkfs.xfs /dev/sdb1. The correct command is mkfs.xfs /dev/sdb1 because the question specifies that the partition must be formatted with XFS. The mkfs.xfs command is the dedicated tool for creating an XFS filesystem on a block device. It directly invokes the mkfs.xfs utility, which writes the XFS superblock and metadata structures to the partition.

Answer

mke2fs /dev/sdb1

Answer

mkfs -t ext4 /dev/sdb1

Answer

mkfs.ext4 /dev/sdb1

Question 9

Refer to the exhibit. The backup script runs every 5 minutes but generates errors. What is the most likely cause?

Accepted Answer

The script is not executable.. The cron job fails because the script lacks execute permissions. Cron requires that scripts specified in crontab entries have the executable bit set (chmod +x) for the user under whose crontab the job runs. Without this, the cron daemon cannot spawn the script as a process, resulting in errors.

Answer

The script is owned by root.

Answer

The cron daemon is not running.

Answer

The script uses absolute paths.

Question 10

An administrator wants to add the two 2G disks (sdc and sdd) as physical volumes, extend the 'data' logical volume in volume group 'vg' by 2G, and grow the filesystem. Which sequence of commands should be used?

Accepted Answer

pvcreate /dev/sdc /dev/sdd; vgextend vg /dev/sdc /dev/sdd; lvextend -L +2G /dev/vg/lv_data; xfs_growfs /data. It follows the correct sequence: create physical volumes on both disks, extend the volume group with both disks in a single command, extend the logical volume by exactly 2G using the `+` sign, and then grow the XFS filesystem using `xfs_growfs` with the mount point `/data`. The `+` in `lvextend -L +2G` is critical to add 2G rather than resize to 2G total, and `xfs_growfs` requires the mount point (or a block device) for XFS filesystems.

Answer

pvcreate /dev/sdc /dev/sdd; vgextend vg /dev/sdc /dev/sdd; lvresize -L 2G /dev/vg/lv_data; xfs_growfs /data

Answer

pvcreate /dev/sdc /dev/sdd; vgextend vg /dev/sdc /dev/sdd; lvextend -L +2G /dev/vg/lv_data; resize2fs /dev/vg/lv_data

Answer

pvcreate /dev/sdc /dev/sdd; vgextend vg /dev/sdc; vgextend vg /dev/sdd; lvextend -L +2G /dev/vg/lv_data; xfs_growfs /dev/vg/lv_data

Question 11

A junior administrator configured a new network interface (ens224) with a static IP address using a configuration file in /etc/sysconfig/network-scripts/ifcfg-ens224. After restarting the network service, the interface comes up but does not get the IP address. The administrator runs 'ip addr show ens224' and sees no IP address assigned. The interface is listed as DOWN. The administrator then runs 'ifup ens224' manually, which succeeds, and the IP address appears. What is the most likely cause?

Accepted Answer

The ONBOOT directive is set to no in the ifcfg file.. The ONBOOT directive controls whether the interface is automatically brought up at system boot. When set to 'no', the interface configuration file is read but the interface remains DOWN after a network service restart, requiring manual intervention via 'ifup'. The junior administrator's observation that 'ifup ens224' succeeds confirms the configuration is valid, but the interface fails to activate automatically due to ONBOOT=no.

Answer

The network service is not enabled to start at boot.

Answer

The interface name does not match the device file.

Answer

There is a conflict with NetworkManager managing the interface.

Question 12

Refer to the exhibit. An administrator attempts to mount the partition but receives an error. Which command should be run first to resolve the issue?

Accepted Answer

file -s /dev/sdc1. The error indicates that the partition /dev/sdc1 does not contain a recognized filesystem. Running 'file -s /dev/sdc1' displays the actual data on the partition, confirming whether a filesystem exists or if the partition is raw. This diagnostic step is essential before any repair or formatting action.

Answer

xfs_repair /dev/sdc1

Answer

partprobe /dev/sdc

Answer

mkfs.xfs /dev/sdc1

Question 13

Refer to the exhibit. What does the file permission -rw------- indicate about /etc/shadow?

Accepted Answer

Only root user can read and write; others have no access.. The permission string `-rw-------` breaks down as: owner (root) has read (4) and write (2) permissions, and no execute (0); group has no permissions (---); others have no permissions (---). Since `/etc/shadow` is owned by root, only the root user can read and write the file, while all other users (including group members and others) have zero access. Option D correctly states this.

Answer

Root user can read, write, and execute; group and others have no access.

Answer

Owner can read and write; group can read; others can read.

Answer

Owner can read; group can read; others cannot access.

Question 14

An administrator needs to create a new 500MB swap partition on a disk that already has an extended partition. The disk /dev/sda has partitions: /dev/sda1 (primary, /boot), /dev/sda2 (extended), /dev/sda5 (logical, swap, 2GB). The administrator wants to add another swap partition, but fdisk shows no free space. Which approach should be used?

Accepted Answer

Use a file-based swap file. The disk has no free space (the extended partition consumes all remaining space after /dev/sda1, and logical partitions are contained within it). Adding a swap file is the simplest and safest approach: it does not require repartitioning, works with any filesystem, and is fully supported by systemd and swapon. The administrator can create a 500MB file, format it as swap with mkswap, and enable it with swapon.

Answer

Use LVM to create a logical volume for swap

Answer

Shrink the filesystem on /dev/sda1 to create free space

Answer

Delete /dev/sda5 and recreate it with larger size

Question 15

After configuring sudo, a user reports: 'sudo: unable to open /etc/sudoers: Permission denied'. The admin checks the file permissions and sees '-rw-r-----' owned by root:root. What is the most likely cause?

Accepted Answer

The file permissions are too permissive (0640 instead of 0440).. The sudoers file requires strict permissions of 0440 (owner read, group read) to be considered secure by sudo. The current permissions of 0640 (owner read/write, group read) are too permissive, as they grant write access to the owner (root), which violates sudo's security model. When sudo detects that /etc/sudoers has permissions other than 0440, it refuses to open the file and reports 'Permission denied' to prevent potential tampering.

Answer

The file is owned by the wrong user.

Answer

The sudo binary is missing the setuid bit.

Answer

SELinux is blocking access.

Question 16

Which command displays the UUID of all file systems on the system?

Accepted Answer

blkid. The `blkid` command is the correct choice because it is specifically designed to locate and display block device attributes, including the UUID, filesystem type, and label, for all filesystems on the system. It reads data from the `/dev/disk/by-uuid/` directory and the `udev` database, making it the most direct and reliable tool for querying UUIDs without requiring root privileges for basic output.

Answer

dumpe2fs -h

Answer

lsblk

Answer

fdisk -l

Question 17

A script needs to execute a command that might fail, but the script should continue. The administrator wants to capture the exit status for logging. Which code snippet correctly implements this?

Accepted Answer

./risky_command; rc=$?; echo $rc. It runs the risky command, captures its exit status immediately after in the `$?` variable, and then echoes it for logging. The script continues regardless of the command's success or failure, which meets the requirement. The `$?` variable holds the exit status of the last executed foreground command, so assigning it to `rc` right after `./risky_command` ensures the correct value is stored.

Answer

set -e; ./risky_command; rc=$?; echo $rc

Answer

rc=$? ./risky_command; echo $rc

Answer

./risky_command && rc=$?; echo $rc

Question 18

A user was recently added to the 'testgrp' group using `usermod -aG testgrp user1`. However, when they try to access a file owned by testgrp with permissions 660, they get permission denied. What is the most likely reason?

Accepted Answer

The user did not log out and log back in.. When a user is added to a supplementary group with `usermod -aG`, the group membership change does not take effect in the user's current login session. The user must log out and log back in (or start a new login shell) for the new group to be recognized by the kernel's process credential system. Without this, the user's process lacks the group ID in its supplementary group list, so access to a file with group permissions (660) is denied.

Answer

The user's primary group is not testgrp.

Answer

The file's group owner is not testgrp.

Answer

The file's ACL overrides group permissions.

Question 19

In /etc/fstab, which values in the dump and pass fields enable automatic file system checking at boot?

Accepted Answer

dump=0, pass=1. The `pass` field in `/etc/fstab` controls the order of file system checks at boot. A value of 1 means the root file system is checked first, and a value of 2 or higher means other file systems are checked after root. The `dump` field is for backup utility (dump) and is not related to boot-time checking; it must be 0 to disable dump. Thus, `dump=0, pass=1` enables automatic file system checking (fsck) at boot for the root file system.

Answer

dump=1, pass=0

Answer

dump=0, pass=0

Answer

dump=1, pass=1

Question 20

A container exits immediately with status 1. The administrator runs 'podman logs container' but sees no output. What is the most likely reason for the missing logs?

Accepted Answer

The container binary is missing or has the wrong architecture (exec format error).. When a container exits immediately with status 1 and `podman logs` shows no output, the most common cause is that the container binary is missing or has the wrong architecture (e.g., an x86 binary on an ARM system). This results in an 'exec format error' that prevents the container's entrypoint from executing, so no stdout/stderr is ever written to the logging driver. The container exits before any process runs, leaving the log buffer empty.

Answer

The container's logging driver is not configured to capture stdout.

Answer

The log file is rotated and cleared.

Answer

The container is using a non-standard log location inside the container.