LPIC-1 Administrative Tasks — 25 Questions

Question 1

A system administrator wants to ensure that the syslog service starts automatically on boot and is running immediately without a reboot. Which command sequence should be used?

Accepted Answer

systemctl enable --now syslog. `systemctl enable --now syslog` combines enabling the service to start automatically on boot and starting it immediately in a single command. The `--now` flag triggers an immediate start after enabling, fulfilling both requirements without needing a reboot.

Answer

systemctl start syslog && systemctl enable syslog

Answer

systemctl start --enable syslog

Answer

systemctl enable syslog && systemctl start syslog

Question 2

A user reports that a cron job is not executing. The cron job is defined in /etc/crontab. The administrator checks the system logs and finds no errors. Which command should the administrator use to verify that the cron daemon is running?

Accepted Answer

pgrep cron. `pgrep cron` searches the process table for processes named 'cron' and returns the PID(s) if running. This is a quick, reliable way to verify the cron daemon is active without parsing full process lists or relying on systemd-specific commands.

Answer

systemctl status cron

Answer

crontab -l

Answer

ps aux | grep cron

Question 3

A system administrator wants to schedule a script to run every Monday at 3:00 AM, but only if the system clock is set to local time (not UTC). Which crontab entry should be used?

Accepted Answer

0 3 * * 1 /path/to/script. The crontab format is 'minute hour day-of-month month day-of-week command'. To run at 3:00 AM Monday, the minute field is 0, the hour field is 3 (using 24-hour time), and the day-of-week field is 1 (Monday). The cron daemon does not care about UTC vs local time; it uses the system's configured timezone, so no special flag is needed.

Answer

3 0 * * 1 /path/to/script

Answer

0 15 * * 1 /path/to/script

Answer

0 3 * * 0 /path/to/script

Question 4

A server has a backup script that runs daily at midnight. The system administrator notices that the script sometimes fails because the filesystem is mounted read-only. Which approach is the best practice to ensure the script runs only when the filesystem is writable?

Accepted Answer

Wrap the backup command in a script that checks if the filesystem is writable before proceeding. It implements a proactive check within the script itself, using a command like `touch /mountpoint/testfile 2>/dev/null` or checking `/proc/mounts` to verify write access before executing the backup. This avoids unnecessary remounts and ensures the script only proceeds when the filesystem is writable, which is a robust and self-contained solution.

Answer

Add a cron job that runs before the backup to remount the filesystem read-write

Answer

Use anacron to run the job after boot

Answer

Change the cron job to run every hour until it succeeds

Question 5

An administrator needs to find all files in the /var/log directory that have been modified in the last 24 hours. Which command should be used?

Accepted Answer

find /var/log -mtime 0. The `find` command with `-mtime 0` searches for files whose data modification time is within the last 24 hours. The `-mtime` option uses a 24-hour period, and a value of 0 means modified less than 24 hours ago, which matches the requirement to find files modified in the last 24 hours in /var/log.

Answer

find /var/log -ctime 0

Answer

find /var/log -atime 0

Answer

find /var/log -mmin 1440

Question 6

A Linux system fails to boot with the error 'Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)'. Which of the following is the most likely cause?

Accepted Answer

The kernel lacks the necessary driver for the storage controller. The error 'VFS: Unable to mount root fs on unknown-block(0,0)' indicates that the kernel cannot find or access the root filesystem. This typically occurs when the kernel lacks the necessary driver (module) for the storage controller (e.g., SATA, SCSI, NVMe) that the root device is connected to. Without the driver, the kernel cannot communicate with the storage hardware, resulting in the unknown-block(0,0) identifier.

Answer

The root filesystem has a corrupted superblock

Answer

The initrd file is missing or corrupted

Answer

The bootloader configuration points to the wrong partition

Question 7

An administrator wants to prevent a specific user, 'john', from being able to schedule cron jobs. Which file should the administrator modify?

Accepted Answer

/etc/cron.deny. The /etc/cron.deny file lists users who are explicitly denied access to schedule cron jobs. If this file exists and the user 'john' is listed in it, he will be prevented from using crontab. This is the standard mechanism for restricting cron access when /etc/cron.allow does not exist.

Answer

/var/spool/cron/crontabs

Answer

/etc/cron.allow

Answer

/etc/crontab

Question 8

Which TWO commands can be used to display the current runlevel of a system?

Accepted Answer

runlevel. The `runlevel` command displays the previous and current runlevel of a SysV init system. The `who -r` command also shows the current runlevel along with the process ID of the init daemon. Both are standard tools for querying runlevel information on systems using SysV init.

Answer

telinit q

Answer

systemctl get-default

Answer

init 3

Question 9

Which THREE of the following statements are true about the /etc/shadow file?

Accepted Answer

It can contain password expiration information. The /etc/shadow file stores password expiration information, such as the last password change date, minimum and maximum password age, warning period, and inactivity period. This data is used by the system to enforce password aging policies, making option B correct.

Answer

It contains the encrypted passwords in the second field, replacing the 'x' in /etc/passwd

Answer

It is world-readable to allow any user to verify passwords

Question 10

Based on the exhibit, which of the following is true about the cleanup.sh job?

Accepted Answer

It runs at 4:30 AM on Monday through Friday. The cron expression `30 4 * * 1-5` specifies that the job runs at minute 30, hour 4 (4:30 AM), every day of month (*), every month (*), but only on days of the week 1 through 5 (Monday=1, Tuesday=2, Wednesday=3, Thursday=4, Friday=5). Therefore, the job runs at 4:30 AM on Monday through Friday.

Answer

It runs at 4:30 AM every day

Answer

It runs at 4:00 AM on weekdays

Answer

It runs at 4:30 AM on weekends

Question 11

Based on the exhibit, what will happen if the syslog service is stopped?

Accepted Answer

Apache2 will continue running because the dependency is a soft dependency. In Linux, services managed by systemd can have dependencies declared as 'Requires' (hard) or 'Wants' (soft). A soft dependency means that the dependent service (Apache2) does not require the target service (syslog) to be running; it will continue to operate even if syslog is stopped. The exhibit likely shows a 'Wants' directive, which does not enforce a strict ordering or runtime requirement.

Answer

Apache2 will be stopped because it depends on syslog

Answer

The system will prompt to restart syslog before stopping

Answer

Apache2 will be automatically restarted because it requires syslog

Question 12

A medium-sized company runs a web application on a Linux server. The server uses systemd and has the following configuration: the web application service (webapp.service) is configured to start after network.target and requires a database service (database.service) to be running. The database service has a Restart=on-failure directive. Recently, the server experienced a power outage. Upon reboot, the system administrator notices that the web application fails to start because the database service is in a failed state. The administrator checks the status of database.service and sees 'inactive (dead)' with no recent attempts to restart. The journal shows that the database service failed to start because a required filesystem (mounted at /var/lib/database) was not mounted when the database service tried to start. The filesystem is listed in /etc/fstab with the nofail option. The administrator wants to ensure that in future reboots, the database service starts successfully and the web application comes up without manual intervention. Which of the following is the best course of action?

Accepted Answer

Modify the database.service unit file to add 'After=var-lib-database.mount' and 'Requires=var-lib-database.mount'. The database service failed due to a missing mount at /var/lib/database. By adding 'After=var-lib-database.mount' and 'Requires=var-lib-database.mount' to the database.service unit, systemd will ensure the mount unit is started before the database service and that the database service is stopped if the mount fails. This directly addresses the root cause—the filesystem not being ready—without altering the restart behavior or the fstab nofail option, which is appropriate for allowing the system to boot even if the mount fails.

Answer

Change the Restart directive in database.service to 'always'

Answer

Remove the nofail option from /etc/fstab for /var/lib/database

Answer

Modify the webapp.service unit file to add 'After=database.service' and 'Requires=database.service'

Question 13

Which TWO commands can be used to display the current runlevel of a SysV init system?

Accepted Answer

who -r. The `who -r` command displays the current runlevel and the time it was last changed, making it a valid way to check the runlevel in a SysV init system. The `runlevel` command directly outputs the previous and current runlevel, which is the standard tool for this purpose.

Answer

init 3

Answer

telinit

Answer

systemctl get-default

Question 14

Refer to the exhibit. An administrator runs 'ntpq -p' and sees the output shown. What is the most likely cause of the '16' stratum and '0.000' delay/offset?

Accepted Answer

The NTP daemon has recently started and has not yet synchronized.. The '16' stratum and '0.000' delay/offset values in the 'ntpq -p' output indicate that the NTP daemon has not yet synchronized with any time source. When ntpd starts, it initially sets the stratum to 16 (unsynchronized) and shows zero values for delay and offset until it completes the synchronization process. This is a normal transient state that resolves once the daemon successfully contacts and synchronizes with an NTP server.

Answer

The NTP service is not running.

Answer

The firewall is blocking UDP port 123.

Answer

The restrict lines are blocking all NTP queries.

Question 15

A Linux administrator is responsible for a server that runs a critical database application. The server uses SysV init and the current runlevel is 3. The administrator needs to schedule a maintenance window for next Sunday at 2:00 AM to apply security patches that require a reboot. The administrator wants to ensure that after the reboot, the system returns to runlevel 3 and the database service (db_service) starts automatically. The administrator also wants to log the maintenance actions to /var/log/maintenance.log. Which of the following is the BEST approach to accomplish these tasks?

Accepted Answer

Edit /etc/rc.d/rc.local to start db_service and set runlevel via 'init 3' in the script. Then use 'at 2am Sunday shutdown -r now' to schedule reboot and redirect output to /var/log/maintenance.log.. The best approach because it uses 'at' to schedule the reboot, which can be configured to run at a specific day and time (e.g., 'at 2am Sunday shutdown -r now'), and redirects output to /var/log/maintenance.log for simple logging. Although editing rc.local is not the standard SysV method for persistent service management, it effectively starts the database service and sets the runlevel to 3 upon boot. In contrast, option B's shutdown command does not allow specifying the day 'next Sunday', and configuring syslog for a custom log file is non-trivial. Options C and D are incorrect due to systemd usage or lack of scheduling.

Answer

Edit /etc/inittab to change the initdefault line to 'id:3:initdefault:' and create an init script for db_service with appropriate symlinks in /etc/rc.d/rc3.d/. Schedule the reboot using 'shutdown -r 02:00' and configure syslog to capture messages to /var/log/maintenance.log.

Answer

Use 'systemctl set-default runlevel3.target' and 'systemctl enable db_service' then schedule reboot with 'shutdown -r 02:00' and log with 'logger' to /var/log/maintenance.log.

Answer

Use 'telinit 3' and 'service db_service start' then run 'reboot' at 2:00 AM. Log actions by appending to /var/log/maintenance.log manually.

Question 16

Arrange the steps to troubleshoot a service that fails to start.

Accepted Answer

Check service status and logs, then examine configuration files, then fix the issue, then restart the service.. Troubleshooting starts with checking status and logs, then examining config files, fixing, and restarting.

Answer

Examine configuration files, then check service status and logs, then fix the issue, then restart the service.

Answer

Check service status and logs, then fix the issue, then examine configuration files, then restart the service.

Answer

Restart the service, then check service status and logs, then examine configuration files, then fix the issue.

Question 17

Match each Linux signal to its default action.

Accepted Answer

SIGINT: Terminate the process. Common Linux signals: SIGINT, SIGTERM, and SIGKILL terminate processes; SIGSTOP and SIGTSTP stop processes; SIGQUIT terminates with a core dump.

Answer

SIGTERM: Stop the process

Answer

SIGKILL: Core dump

Answer

SIGTSTP: Terminate the process

Question 18

An administrator needs to check the system's load averages without displaying any process information. Which command should be used?

Accepted Answer

uptime. The `uptime` command displays the current time, how long the system has been running, the number of logged-in users, and the system load averages for the past 1, 5, and 15 minutes. It does not show any process-level information, making it the correct choice for checking load averages alone.

Answer

w

Answer

top

Answer

ps

Question 19

An administrator adds the line 'DenyUsers john' to /etc/ssh/sshd_config and restarts the SSH service. What is the effect?

Accepted Answer

User john cannot log in via SSH.. The 'DenyUsers' directive in /etc/ssh/sshd_config explicitly blocks the specified user(s) from authenticating via SSH. When the SSH service is restarted, the configuration is reloaded, and user 'john' will be denied SSH login attempts at the authentication layer, before any shell or command execution occurs.

Answer

User john can still log in but his commands are logged.

Answer

User john is denied all shell access, including local and console logins.

Answer

All users except john cannot log in via SSH.

Question 20

Which command is used to view the last few lines of a log file and simultaneously follow new entries as they are written?

Accepted Answer

tail -f. The `tail -f` command is correct because it displays the last 10 lines of a file by default and then continues to monitor the file for new lines, outputting them as they are appended. This is essential for real-time log monitoring, as it uses inotify or polling to detect file changes without requiring manual re-reading.

Answer

cat

Answer

head -n 10

Answer

less