LPIC-1 Practice Test 13 — 15 Questions

Question 1

You are the system administrator for a small business running a Red Hat Enterprise Linux 8 server that hosts a MySQL database and a web server. The server has two physical disks: a 240GB SSD (sda) with partitions sda1 (boot), sda2 (root), sda3 (swap), and a 1TB HDD (sdb) with a single partition sdb1 mounted at /var/lib/mysql. The server has been running for months without issues. However, this morning you receive alerts that the MySQL database is not accepting new connections. You log in and find that the /var filesystem is 100% full. You check the disk usage and see that /var/lib/mysql uses 90% of the space, but there are also large log files in /var/log/httpd. To free up space immediately and restore database service while planning a permanent solution, you decide to compress old log files and move some database archives to a backup server. After compressing several log files with gzip, the available space increases by only a few MB. You then delete some old database backups from /var/lib/mysql/backup, but the space usage shown by df remains unchanged. What is the most likely cause of this behavior?

Accepted Answer

Some processes have open file handles to the deleted files, preventing the space from being released.. When a file is deleted but still held open by a running process (e.g., the MySQL daemon or httpd), the filesystem does not release the disk space until all file handles are closed. In this scenario, the large log files in /var/log/httpd were compressed with gzip, but the original uncompressed files may still be open by the web server process, so deleting them (or the old database backups) does not free space until the process is restarted or the handles are released. This explains why df still shows 100% usage despite the deletions.

Answer

The disk quota for the mysql user is exceeded, so deletions do not reduce usage.

Answer

The SSD is not TRIM-enabled, so deleted blocks are not reclaimed.

Answer

The filesystem was remounted read-only due to errors, so deletions are not permanent.

Question 2

An application assumes its data is stored in /opt/app/data, but the /opt filesystem is running out of space. The administrator moves the data to /var/app/data. Which method will allow the application to continue accessing the data at /opt/app/data without modifying the application's configuration?

Accepted Answer

Use mount --bind /var/app/data /opt/app/data. Option C is correct because `mount --bind` creates a bind mount that makes the contents of `/var/app/data` appear at `/opt/app/data` without moving or copying files. The application continues to access the data at the original path, and the kernel transparently redirects all filesystem operations to the new location. This avoids modifying the application's configuration or creating a symbolic link that might not be followed by all programs (e.g., those using `chroot` or running with restricted permissions).

Answer

Use ln -s /var/app/data /opt/app/data

Answer

Edit /etc/fstab to mount /var/app/data at /opt/app/data

Answer

Create a symbolic link /opt/app/data -> /var/app/data

Question 3

A system administrator needs to check if a filesystem has any errors without actually performing a repair. Which command should be used?

Accepted Answer

fsck -n /dev/sdb1. The `-n` option with `fsck` performs a read-only check, displaying any filesystem errors without making any modifications or repairs. This is the correct choice for a non-destructive check that only reports issues.

Answer

fsck -y /dev/sdb1

Answer

fsck -N /dev/sdb1

Answer

e2fsck -p /dev/sdb1

Question 4

Refer to the exhibit. The system logs show the above messages. What is the most likely cause and the correct first action?

Accepted Answer

Filesystem corruption occurred; unmount and run fsck.. The kernel log messages indicate a filesystem I/O error (e.g., 'EXT4-fs error (device sda1)') which typically points to filesystem corruption. Running fsck on the unmounted filesystem is the correct first action to repair the metadata and recover the filesystem. Option B is correct because fsck is the standard tool for checking and repairing filesystem inconsistencies.

Answer

The filesystem is read-only; remount with 'mount -o remount,rw /'.

Answer

The device is unresponsive; replace the disk.

Answer

The filesystem is full; delete unnecessary files.

Question 5

An administrator notices that a large file on an ext4 filesystem is taking up more disk space than expected based on its size. Which command would show the actual disk usage (block allocation) of the file?

Accepted Answer

du -h. Option C (du -h) is correct because du (disk usage) reports the actual disk space consumed by a file, including allocated blocks, which can be larger than the file's logical size due to block size overhead, fragmentation, or sparse file handling. On ext4, the default block size is 4096 bytes, so a 1-byte file occupies 4096 bytes on disk, and du reflects this allocation.

Answer

ls -l

Answer

df -h

Answer

stat

Question 6

Refer to the exhibit. An administrator attempts to remount /mnt as read-only but receives the error shown. What is the most likely cause?

Accepted Answer

The /mnt directory is not a mount point. The error 'mount: /mnt is not a mount point' indicates that the administrator attempted to use the `remount` option on a directory that is not currently a mount point. The `mount -o remount` command only works on directories where a filesystem is already mounted; it modifies the mount options of an existing mount, not a regular directory. Since /mnt is not a mount point, the kernel rejects the operation with this specific error.

Answer

The /mnt directory is not empty

Answer

The /mnt directory does not exist

Answer

The filesystem is already mounted read-only

Question 7

A system administrator needs to locate the largest directories under /var to free up disk space. Which command is most appropriate?

Accepted Answer

du -sk /var/* | sort -rn. Option D is correct because `du -sk /var/* | sort -rn` calculates the disk usage in kilobytes for each top-level item under /var, then sorts them numerically in reverse order, showing the largest directories first. This directly addresses the need to locate the largest directories to free up space, as `du` reports actual disk usage (including subdirectories) rather than file sizes.

Answer

df -h /var

Answer

find /var -size +100M

Answer

ls -lS /var

Question 8

You are a junior system administrator tasked with adding a new 500GB HDD to a Debian 11 server that will be used for backup storage. The server currently has a 120GB SSD with two partitions: sda1 (boot) and sda2 (root). You have physically installed the HDD and it is recognized as /dev/sdb. You need to partition the disk with a single partition covering the entire disk, format it as ext4, and ensure it is automatically mounted at /backup at boot time. Which sequence of commands should you execute to accomplish this?

Accepted Answer

sudo parted /dev/sdb mklabel gpt && sudo parted /dev/sdb mkpart primary ext4 0% 100% && sudo mkfs.ext4 /dev/sdb1 && echo '/dev/sdb1 /backup ext4 defaults 0 2' | sudo tee -a /etc/fstab && sudo mount -a. Option A is correct because it first creates a GPT partition table on /dev/sdb with parted, then creates a single primary partition spanning the entire disk, formats that partition (not the raw disk) as ext4, adds an fstab entry for automatic mounting at /backup, and finally mounts all filesystems. This sequence ensures the disk is properly partitioned, formatted, and configured for persistent boot-time mounting.

Answer

sudo mkfs.ext4 /dev/sdb1 && echo '/dev/sdb1 /backup ext4 defaults 0 2' | sudo tee -a /etc/fstab && sudo mount -a

Answer

sudo mkfs.ext4 /dev/sdb && echo '/dev/sdb /backup ext4 defaults 0 2' | sudo tee -a /etc/fstab && sudo mount -a

Answer

sudo fdisk /dev/sdb (create partition) && sudo mkswap /dev/sdb1 && echo '/dev/sdb1 /backup ext4 defaults 0 2' | sudo tee -a /etc/fstab && sudo mount -a

Question 9

Which TWO commands can be used to create an ext4 filesystem on a partition?

Accepted Answer

mkfs.ext4 /dev/sdb1. The `mkfs.ext4` command is a direct front-end for creating an ext4 filesystem, making option B correct. Option C is also correct because `mke2fs -t ext4` explicitly calls the ext2/3/4 filesystem creation tool with the ext4 type, producing an identical ext4 filesystem. Both commands ultimately invoke the same underlying `mke2fs` utility with the appropriate filesystem type.

Answer

mkfs.btrfs /dev/sdb1

Answer

mkfs.msdos /dev/sdb1

Answer

mkfs.xfs /dev/sdb1

Question 10

A systems administrator needs to find all files in /var/log that were modified in the last 24 hours and contain the word 'error'. Which command accomplishes this?

Accepted Answer

find /var/log -mtime 0 -exec grep -l 'error' {} \;. Option B is correct because it uses `find` with `-mtime 0` to locate files modified within the last 24 hours, then pipes each found file to `grep -l` to print only filenames containing 'error'. The `-exec` option runs `grep` on each file individually, and `-l` ensures only matching filenames are output, not the matching lines.

Answer

grep -r 'error' /var/log -mtime 0

Answer

find /var/log -mmin 1440 -exec grep 'error' {}

Answer

ls -l /var/log | grep error

Question 11

A developer is troubleshooting a shell script that uses the variable $HOME but it outputs nothing when the script runs. The script is executed with ./script.sh from an interactive shell. What is the most likely cause?

Accepted Answer

The HOME variable is not exported. Option C is correct because the HOME variable is typically set by the login process and exported to the environment. If the script is run in a context where HOME is not exported (e.g., a non-interactive shell or a script that clears the environment), the variable will be empty. The script uses $HOME, which expands to nothing if HOME is unset or not exported, causing the output to be empty.

Answer

The script is run with sh instead of bash

Answer

The script is run with sudo

Answer

The user has no home directory

Question 12

A script uses 'set -e' and then executes 'grep pattern file'. If the pattern is not found, the script exits. Which of the following modifications would prevent the script from exiting while still allowing detection of the pattern's absence?

Accepted Answer

set +e; grep pattern file; exit_code=$?; set -e. Option B is correct because it temporarily disables 'set -e' with 'set +e', runs the grep command, captures its exit code in a variable, then re-enables 'set -e'. This allows the script to continue executing after a non-zero exit from grep, while still preserving the exit code for later conditional checks. The other options either fail to preserve the exit code or do not prevent the script from exiting under 'set -e'.

Answer

grep -q pattern file || true

Answer

grep pattern file; exit_code=$?

Answer

grep pattern file | head -1

Question 13

Refer to the exhibit. The process with PID 1234 is in state 'Z'. What is the most likely cause and appropriate action?

Accepted Answer

The process is a zombie; the parent process must be killed or wait for it to be reaped.. In Linux process states, 'Z' indicates a zombie process, which is a child process that has terminated but whose exit status has not yet been read by its parent process via the wait() system call. The correct action is to either kill the parent process (so that the zombie is reaped by init) or ensure the parent calls wait() to reap the child. Option D correctly identifies this.

Answer

The process is stopped; use kill -CONT to continue.

Answer

The process is a daemon; it should be restarted.

Answer

The process is sleeping; wait for it to become ready.

Question 14

Which TWO commands can be used to display the contents of a compressed file without decompressing it to disk? (Choose two.)

Accepted Answer

zcat file.gz. A is correct because `zcat` reads a gzip-compressed file and writes its decompressed content to standard output without saving the decompressed data to disk. This allows you to view the contents of `file.gz` directly in the terminal or pipe it to other commands.

Answer

gzip -d file.gz

Answer

tar -xzf file.tar.gz

Answer

uncompress file.Z

Question 15

Which TWO commands can be used to display the contents of a compressed text file (e.g., .gz, .bz2) directly to standard output without decompressing to disk?

Accepted Answer

bzcat. Option C (bzcat) is correct because it reads bzip2-compressed files (.bz2) and decompresses them directly to standard output without creating a decompressed file on disk. Option E (zcat) is correct because it does the same for gzip-compressed files (.gz), acting as a front-end to gzip -dc.

Answer

gzcat

Answer

zless

Answer

lzcat