LPIC-1 Practice Test 30 — 15 Questions

Question 1

A junior administrator is asked to verify which TCP ports are listening on a Linux server and which processes own them. Which command provides this information directly?

Accepted Answer

ss -tulpn. The ss command with -tulpn is the standard tool on modern Linux to list listening TCP and UDP sockets, show numeric addresses, and map them to owning processes. Netstat -r shows routes, ip link show displays interface state, and lsof -i :22 is limited to a single port. Only ss -tulpn provides a comprehensive view of all listening ports and their processes.

Answer

netstat -r

Answer

lsof -i :22

Answer

ip link show

Question 2

An administrator needs to install a package named 'nginx' on a Debian system, but the package is already installed. The administrator wants to ensure that the latest available version from the configured repository is installed, upgrading if necessary. Which command should be used?

Accepted Answer

apt-get install nginx. apt-get install nginx will install the package if not present, or upgrade it to the newest version if one is available in the repositories. It automatically handles dependencies and is the standard method for ensuring a package is at the latest available version on Debian systems.

Answer

dpkg -i nginx

Answer

apt-get reinstall nginx

Answer

apt-get upgrade nginx

Question 3

A user wants to view the contents of a large text file one page at a time, with the ability to scroll both forward and backward. Which command should the user employ?

Accepted Answer

less. The less command is specifically designed for paging through text files, allowing forward and backward scrolling, searching, and other navigation. Unlike cat, which dumps the entire file, or head/tail, which show only portions, less provides an interactive viewing experience ideal for large files. It is a standard tool in Linux environments.

Answer

tail

Answer

head

Answer

cat

Question 4

A user needs to find all lines in a file that contain the word `error` while ignoring case, and also print the line number for each match. Which TWO `grep` invocations accomplish this? (Choose two.)

Accepted Answer

grep -in error file.log. Case-insensitive matching is enabled by `-i`, and line numbers are added by `-n`. Whether written as `-in` or as separate `-i -n` options, both forms satisfy the requirement to list matching lines with their line numbers. The other options invert the match, print only a count, or print only filenames, none of which meets the stated goal.

Answer

grep -l -i error file.log

Answer

grep -c -n error file.log

Answer

grep -v -n error file.log

Question 5

A user reports that a USB flash drive plugged into a Linux workstation is not automatically mounted. The administrator runs 'lsblk' and sees the device as /dev/sdb1 with no mountpoint. Which command should the administrator use to manually mount the filesystem on /dev/sdb1 to the /mnt/usb directory?

Accepted Answer

mount /dev/sdb1 /mnt/usb. The correct command is 'mount /dev/sdb1 /mnt/usb'. This uses the standard syntax of device followed by mount point. The system will auto-detect the filesystem type. Other options either reverse the arguments, add unnecessary options, or use loop mounting which is not applicable.

Answer

mount -t auto /dev/sdb1 /mnt/usb

Answer

mount /mnt/usb /dev/sdb1

Answer

mount -o loop /dev/sdb1 /mnt/usb

Question 6

A junior administrator on a systemd host needs the OpenSSH daemon to start automatically after every reboot and to begin running immediately without rebooting the machine. Which single command accomplishes both requirements?

Accepted Answer

systemctl enable --now sshd.service. Persisting a service across boots requires enabling it so systemd creates the appropriate wants symlinks, while running it right away requires an active start. The enable --now combination performs both operations atomically, so the daemon is active and will also be pulled in at every subsequent boot without an intervening reboot or a second command.

Answer

systemctl start sshd.service

Answer

systemctl enable sshd.service

Answer

systemctl daemon-reload

Question 7

A user wants to set a shell variable named DEPLOY_ENV to the value 'staging' in the current Bash session so that child processes can read it. Which command accomplishes this?

Accepted Answer

export DEPLOY_ENV=staging. To make a variable available to child processes, it must be exported into the environment. The export builtin, used together with an assignment, both sets the variable in the current shell and ensures it is inherited by subsequently launched commands. A plain assignment stays local to the shell, set controls shell options, and env without a command only displays the environment.

Answer

DEPLOY_ENV=staging

Answer

set DEPLOY_ENV=staging

Answer

env DEPLOY_ENV=staging

Question 8

A system administrator suspects that a particular service is failing to start at boot. The service is managed by systemd. Which command will show the current status of the service, including whether it is active, and recent log entries?

Accepted Answer

systemctl status servicename.service. The correct command is systemctl status servicename.service. It provides a concise status summary, including whether the service is active, its main PID, and recent log entries. The other commands either show only properties, only logs, or a list of all services, lacking the combined status and log view needed for quick diagnosis.

Answer

journalctl -u servicename.service

Answer

systemctl list-units --type=service

Answer

systemctl show servicename.service

Question 9

A developer needs to run a script named `backup.sh` every day at 02:30 using the system-wide cron facility. The system uses a traditional cron daemon and the file `/etc/crontab` contains a `SHELL` and `PATH` line. Which entry in `/etc/crontab` correctly schedules the script to run as user 'backup'?

Accepted Answer

30 2 * * * backup /usr/local/bin/backup.sh. The system-wide `/etc/crontab` file has a distinct format that includes a username field before the command. The correct syntax is: minute hour day-of-month month day-of-week user command. The entry `30 2 * * * backup /usr/local/bin/backup.sh` schedules the script at 02:30 daily and runs it as the 'backup' user. Entries without the user field are valid only in per-user crontabs created with `crontab -e`.

Answer

30 2 * * * root run-parts /usr/local/bin/backup.sh

Answer

30 2 * * * backup /bin/sh /usr/local/bin/backup.sh

Answer

30 2 * * * /usr/local/bin/backup.sh

Question 10

A junior administrator needs to extract only the file 'etc/nginx/nginx.conf' from the archive 'backup.tar.bz2' into the current directory, preserving its path structure. Which command should be used?

Accepted Answer

tar -xjvf backup.tar.bz2 etc/nginx/nginx.conf. To extract a single file from a bzip2-compressed tarball while keeping its stored path, use tar with -x, -j, -v, and -f, followed by the exact member name. Omitting -j would fail on bzip2 compression, and using -c would create rather than extract. The member name must match the archived path exactly to select only that file.

Answer

tar -xjf backup.tar.bz2 --strip-components=1 etc/nginx/nginx.conf

Answer

tar -xjvf backup.tar.bz2 | grep nginx.conf

Answer

tar -cjvf backup.tar.bz2 etc/nginx/nginx.conf

Question 11

A Linux administrator is preparing a new server and needs to create an ext4 filesystem on the /dev/sdb1 partition. Which command should be used?

Accepted Answer

mkfs -t ext4 /dev/sdb1. The mkfs command is the standard utility for creating filesystems. Using mkfs -t ext4 /dev/sdb1 explicitly specifies the ext4 filesystem type. This invokes the mkfs.ext4 program, which writes the ext4 superblock, inode tables, and journal to the partition. Other commands like fsck and tune2fs are for checking or modifying existing filesystems, not for creation.

Answer

fsck.ext4 /dev/sdb1

Answer

tune2fs -t ext4 /dev/sdb1

Answer

mke2fs -j /dev/sdb1

Question 12

A user reports that they cannot create new files in their home directory even though the filesystem shows free space. Running df -h shows the filesystem at 100 percent inode usage. Which action most directly resolves the immediate problem?

Accepted Answer

Delete unneeded files that consume many inodes, such as old session files or cached mail, to free inode entries.. When df -h reports 100 percent inode usage, the filesystem has no free inode entries even though data blocks may remain. Deleting many small files, such as session or cache files, releases inodes and restores file creation. Expanding the filesystem, remounting with noatime, or adjusting the check interval do not increase available inodes and therefore do not fix the immediate issue.

Answer

Run resize2fs to expand the filesystem onto additional space.

Answer

Remount the filesystem with the noatime option to stop inode updates.

Answer

Increase the inode count by running tune2fs -i 0 on the mounted filesystem.

Question 13

A junior administrator is monitoring a long-running data migration and wants the 'df -h' output for the /data mount point to refresh automatically on screen every 5 seconds, replacing the previous output each time. Which command accomplishes this?

Accepted Answer

watch -n 5 df -h /data. The watch command is purpose-built for periodically re-running a program and overwriting the terminal display with its newest output. Supplying -n 5 sets the refresh interval to five seconds, and appending the df invocation with the /data path limits monitoring to that mount point. This satisfies the need for hands-free, continuously updated usage information.

Answer

nohup df -h /data &

Answer

at now + 5 minutes -f df -h /data

Answer

sleep 5 && df -h /data

Question 14

An administrator needs to gather detailed information about the partition table and filesystem geometry of /dev/sda before migrating data. Which TWO commands will display the partition layout of the disk? (Choose two.)

Accepted Answer

fdisk -l /dev/sda. Both fdisk -l and parted print read and display the on-disk partition table, enumerating partitions with their start and end positions and the table type. The other tools focus on filesystem identity or capacity rather than partitioning: blkid and lsblk -f describe what filesystems exist, and df reports mount usage. For migration planning that requires partition geometry, the partition-table readers are the correct choices.

Answer

lsblk -f /dev/sda

Answer

blkid /dev/sda

Answer

df -h /dev/sda

Question 15

A junior administrator runs `ps aux` and sees a process owned by user 'deploy' with STAT code 'T'. The process is a long-running data migration script. The administrator wants to know what this status means and what will happen if no action is taken. Which statement correctly describes the process state?

Accepted Answer

The process is stopped (suspended) and will not run until it receives SIGCONT or is resumed.. The STAT column of `ps` encodes process state. Uppercase 'T' means the process has been stopped by a job-control signal (SIGSTOP, SIGTSTP, or SIGTTIN/SIGTTOU) and is not running. To resume it, send SIGCONT or use shell job control. Without intervention, a stopped process makes no progress, which can stall a migration indefinitely.

Answer

The process is in an uninterruptible sleep, usually waiting for I/O, and cannot be killed until the I/O completes.

Answer

The process is a zombie and its parent has not yet reaped it, so it consumes no CPU but remains in the process table.

Answer

The process is being traced by a debugger and is currently paused at a breakpoint.