EX200 Practice Test 15 — 15 Questions

Question 1

You maintain a script that performs a long-running task and must clean up temporary files if the script is interrupted. The script uses:

#!/bin/bash
tempfile=$(mktemp)
trap "rm -f $tempfile" EXIT
# long task
sleep 100

You notice that if the script receives SIGINT (Ctrl+C), the temporary file is not removed. Investigation shows that the trap on EXIT is not executed on SIGINT. Which modification should be made?

Accepted Answer

Add a trap for INT: `trap "rm -f $tempfile; exit" INT`.. The EXIT trap is only triggered on normal script termination (e.g., reaching the end or an explicit `exit`), not on signals like SIGINT. By adding a separate trap for INT that explicitly removes the temp file and calls `exit`, the cleanup runs even when the user presses Ctrl+C, ensuring the temporary file is deleted.

Answer

Move the trap inside a subshell: (trap ... EXIT; long task).

Answer

Change `trap ... EXIT` to `trap ... 0`.

Answer

Add `set -e` at the beginning of the script.

Question 2

Refer to the exhibit. What effect does the value INACTIVE=-1 have on newly created user accounts?

Accepted Answer

The password inactivity period is disabled.. The `INACTIVE=-1` setting in the `useradd -D` or `/etc/default/useradd` configuration disables the password inactivity period. This means that after a password expires, the account will not be locked due to inactivity, effectively turning off the inactivity timer. The value -1 is a special sentinel that indicates no inactivity period is enforced.

Answer

The account expires immediately.

Answer

Passwords never expire.

Answer

Account is disabled if password expires but user does not log in within -1 days (immediately).

Question 3

Refer to the exhibit. An administrator runs xfs_growfs on /dev/sdc1. What is the most likely reason the command succeeded without prior partition resizing?

Accepted Answer

The underlying block device (partition or logical volume) was extended before the command. xfs_growfs can only expand an XFS filesystem to fill the available space on the underlying block device. If the command succeeded without prior partition resizing, it means the block device (e.g., a partition or logical volume) was already extended beforehand. The filesystem then uses the new space when xfs_growfs is run.

Answer

The partition was automatically resized by xfs_growfs

Answer

The filesystem was already using the full partition size and the command had no effect

Answer

The filesystem was mounted with the 'grow' option allowing online growth

Question 4

A system administrator is setting up storage for a new application server. The application requires two separate filesystems: one for the database (needs to be at least 10GiB) and one for logs (needs at least 5GiB). The server has a single 20GiB disk /dev/sda. The administrator plans to use LVM and a single volume group 'vg_app'. They create physical volume on /dev/sda, create the volume group, and then create two logical volumes: 'lv_db' of 10GiB and 'lv_logs' of 5GiB. They format lv_db as ext4 and lv_logs as xfs, and mount them at /db and /logs respectively. After rebooting, the system fails to mount /logs. What is the most likely cause?

Accepted Answer

The /logs entry is missing from /etc/fstab.. The most likely cause is that the /logs entry is missing from /etc/fstab. After reboot, the system relies on /etc/fstab to mount filesystems automatically. Since the administrator created and mounted the filesystem manually, but did not add an entry for /logs in /etc/fstab, the mount fails on reboot. The database mount may succeed if it was added, but the logs mount fails due to the missing fstab entry.

Answer

The logical volume 'lv_logs' overlaps with 'lv_db'.

Answer

The physical volume /dev/sda is not recognized by LVM after reboot.

Answer

The volume group 'vg_app' is not automatically activated.

Question 5

An administrator needs to grant user 'dev' the ability to execute /usr/local/bin/deploy.sh as root without a password, but no other commands. Which sudoers entry accomplishes this?

Accepted Answer

dev ALL=(root) NOPASSWD: /usr/local/bin/deploy.sh. The sudoers entry 'dev ALL=(root) NOPASSWD: /usr/local/bin/deploy.sh' grants user dev permission to run only that command as root without a password prompt. The NOPASSWD tag removes the password requirement, and specifying the single command restricts the privilege to exactly that binary.

Answer

dev ALL=(root) PASSWD: /usr/local/bin/deploy.sh

Answer

dev ALL=(ALL) NOPASSWD: /usr/local/bin/deploy.sh

Answer

%dev ALL=(root) NOPASSWD: /usr/local/bin/deploy.sh

Question 6

An administrator wants to extend an XFS filesystem that resides on an LVM logical volume. The volume group has free physical extents. Which is the correct sequence?

Accepted Answer

lvextend, then xfs_growfs. To extend an XFS filesystem on an LVM logical volume, you must first extend the logical volume with `lvextend` to allocate additional physical extents from the volume group, then grow the XFS filesystem to use the new space with `xfs_growfs`. XFS does not support online shrinking and requires the filesystem to be mounted for `xfs_growfs` to work. This sequence ensures the block device has sufficient capacity before the filesystem is expanded.

Answer

lvextend, then resize2fs

Answer

xfs_growfs, then lvextend

Answer

resize2fs, then lvextend

Question 7

Refer to the exhibit. After extending the logical volume, why does the df output still show 5.0G?

Accepted Answer

The filesystem needs to be resized with xfs_growfs.. The output shows the logical volume was extended (e.g., from 5G to 10G), but the filesystem itself has not been resized to use the new space. For XFS filesystems, the `xfs_growfs` command must be run to expand the filesystem to match the logical volume size. The `df` command reports filesystem usage, not block device size, so it still shows 5.0G until the filesystem is grown.

Answer

The lvextend command failed silently.

Answer

The filesystem type is ext4 and requires resize2fs.

Answer

The mount point /data is not accessible.

Question 8

Refer to the exhibit. If the system administrator wants to create a new logical volume of size 2GB in the 'rhel' volume group, what is the first command that must be executed?

Accepted Answer

pvcreate /dev/sdb1. Before a new logical volume can be created in the 'rhel' volume group, the physical volume must be prepared. The exhibit shows that /dev/sdb is not yet partitioned; the first step is to create a partition (e.g., /dev/sdb1) and then initialize it as a physical volume using `pvcreate /dev/sdb1`. Only after this can the volume group be extended and the logical volume created.

Answer

pvcreate /dev/sdb

Answer

lvcreate -L 2G -n lvdata rhel

Answer

vgextend rhel /dev/sdb

Question 9

Which command shows the amount of disk space used and available on each mounted filesystem?

Accepted Answer

df -h. The `df -h` command displays disk space usage for all mounted filesystems, showing total, used, and available space in human-readable format (e.g., GB, MB). This directly answers the question about disk space on each mounted filesystem.

Answer

fdisk -l

Answer

du -sh

Answer

lsblk

Question 10

Which of the following is the correct way to persistently mount a filesystem using its UUID?

Accepted Answer

UUID=1234 /mnt xfs defaults 0 0. The /etc/fstab entry uses the 'UUID=' prefix followed by the actual UUID value to persistently mount a filesystem. The kernel reads this line at boot time and resolves the UUID to the corresponding block device, ensuring the mount is consistent regardless of device name changes.

Answer

LABEL=1234 /mnt xfs defaults 0 0

Answer

/dev/disk/by-uuid/1234 /mnt xfs defaults 0 0

Answer

PARTUUID=1234 /mnt xfs defaults 0 0

Question 11

Which TWO of the following are true about creating simple shell scripts in Red Hat Enterprise Linux?

Accepted Answer

The shebang line (e.g., #!/bin/bash) is used to specify the interpreter.. The shebang line (e.g., #!/bin/bash) tells the kernel which interpreter to use when executing the script. Without it, the shell may fall back to the default interpreter (often /bin/sh) or fail to run the script correctly. This is a fundamental requirement for any interpreted script in Linux.

Answer

Scripts must be stored in /usr/local/bin to be found by the shell.

Answer

A script must be compiled before it can be run.

Answer

A script must have a .sh file extension to be executable.

Question 12

Which THREE actions will create a new empty file named 'testfile' in the current directory? (Choose three.)

Accepted Answer

> testfile. The shell redirection operator `>` without a preceding command truncates or creates the specified file. When used alone, `> testfile` opens 'testfile' for writing, which creates an empty file if it does not exist, or truncates it to zero length if it does. This is a standard POSIX shell feature.

Answer

ls > testfile

Answer

echo "content" > testfile

Question 13

A developer needs to compile software from source and install it under /opt/custom. To avoid affecting the system package manager, which approach should be used?

Accepted Answer

Compile with './configure --prefix=/opt/custom' and then 'make install'. Using `./configure --prefix=/opt/custom` sets the installation root to `/opt/custom`, which keeps the compiled software completely separate from the system-managed directories (e.g., `/usr`, `/usr/local`). Running `make install` then installs all files under this custom prefix, ensuring the system package manager (RPM/YUM/DNF) is not affected by the manual installation.

Answer

Compile and install with default paths, then use 'make uninstall' to remove

Answer

Compile with './configure --prefix=/opt/custom' and use 'checkinstall' to create an RPM

Answer

Compile with './configure --prefix=/usr' and then install

Question 14

Which THREE options are valid when creating a new partition with the 'parted' command? (Choose three.)

Accepted Answer

Setting the partition's bootable flag. The 'parted' command can set the bootable flag on a partition using the 'set' command (e.g., 'set 1 boot on'). This flag is used by legacy BIOS bootloaders to identify the active partition, and it is a standard operation in MBR and GPT partition tables.

Answer

Setting the partition's UUID

Answer

Mounting the partition to a directory

Question 15

A system administrator needs to run a container that remains running in the background and executes a web server. Which podman command will correctly run the container detached and map host port 8080 to container port 80?

Accepted Answer

podman run -d -p 8080:80 nginx. `podman run -d` runs the container in detached mode (background), and `-p 8080:80` maps host port 8080 to container port 80, which is the standard port for the nginx web server. This allows external traffic on host port 8080 to be forwarded to the nginx service inside the container.

Answer

podman run -d -p 80:8080 nginx

Answer

podman run -d --expose 80 nginx

Answer

podman run -d -P 8080:80 nginx