Unit 2: Permissions, Processes, Services, SSH, and Logs - Practice Quiz

1 Which three basic permissions can be assigned to a Linux file?

2 Which command changes the permissions of a file?

3 Which command displays or sets the permission mask used when creating new files and directories?

4 What is a process in Linux?

5 Which command lists jobs started from the current shell?

6 Which signal does the kill command send by default?

7 Which command provides a continuously updated view of running processes?

8 What is a daemon in Linux?

9 Which command checks whether a systemd service is enabled to start automatically?

10 Which command starts a service named httpd immediately?

11 Which file is the main server configuration file for the OpenSSH daemon?

12 Which command connects to the host server1 using the account student?

13 On the remote system, which file normally stores public keys authorized for SSH login?

14 Which directive in sshd_config changes the port on which the SSH server listens?

15 What is the main purpose of log rotation?

16 Which systemd component collects and stores journal messages?

17 Which command displays the last lines of a text-based log file?

18 Which command displays entries stored in the systemd journal?

19 Which directory is commonly created to enable persistent systemd journal storage?

20 Which command displays the current system time and time synchronization status on a systemd-based system?

21 A directory has permissions drwxr-x--- and is owned by alice:developers. What can user bob, who belongs to the developers group, do in this directory?

22 A regular file has mode 640 and is owned by root:finance. Which permission set does this represent?

23 You need to give the group execute permission on deploy.sh while leaving every other permission unchanged. Which command should you use?

24 A process creates regular files with a base mode of 666. If its umask is 027, what permissions will a newly created file normally receive?

25 Members of the project group share /srv/project. New files must inherit the directory's group ownership. Which change provides this behavior?

26 A shell launches a command and receives PID 8420. Which statement correctly describes the PPID shown for that command?

27 You suspend a foreground command by pressing Ctrl+Z. Which command resumes job number 2 in the background?

28 A process is unresponsive, but you want to allow it to perform normal cleanup before stopping. Which command should you try first for PID 4187?

29 A server feels slow, and you need an updating view that can sort processes by CPU usage. Which command is most appropriate?

30 A process has a nice value of 10, while another has a nice value of 0. Under similar CPU demand, what does this imply?

31 On a systemd-based server, which command shows enabled service unit files that are configured to start automatically?

32 You need httpd to start now and also start automatically after future boots. Which command performs both actions?

33 After editing a systemd unit file on disk, which command makes systemd reload unit definitions before you restart the service?

34 The SSH daemon on server.example.com listens on port 2222. Which command connects as user admin?

35 You generated a key pair on a client and need to install the public key for account admin on host1. Which command is designed for this task?

36 An SSH server should reject direct root logins while still allowing other authorized users. Which sshd_config directive implements this requirement?

37 Before restarting sshd after modifying /etc/ssh/sshd_config, which command checks the configuration for syntax errors?

38 On a distribution that stores general system messages in /var/log/messages, which command follows newly appended log entries in real time?

39 A service named backup.service failed during the current boot. Which command displays journal entries only for that unit and boot?

40 A system currently keeps journal data only in volatile storage. Which change commonly enables persistent journal storage across reboots?

41 A shared directory has mode 2770, is owned by root:developers, and contains files created by multiple members of developers. Members must continue inheriting the directory's group, but they must not be able to delete or rename files owned by other members. Which command best implements this requirement?

42 A root-owned executable initially has mode 4711. Assuming the command is run by root, what mode results from chmod u-s,g+s,o-rwx program?

43 A tree contains directories with mode 755, executable scripts with mode 755, and data files with mode 644. An administrator runs:

chmod -R a-x TREE && chmod -R u=rwX,g=rX,o= TREE

What is the resulting access mode pattern?

44 A process has umask 0027. It requests mode 0660 when creating a regular file and mode 0770 when creating a directory. Assuming no default ACLs are present, which modes are created?

45 A service has accumulated many zombie child processes. Sending SIGKILL to the zombie PIDs has no effect. Which action most directly resolves the existing zombies?

46 An unprivileged user owns a process whose nice value is 5. The user runs renice -n 10 -p PID. What is the expected result on a standard Linux system?

47 A foreground job already has all input and output redirected to files. The operator presses Ctrl-Z and wants it to continue in the background, remain listed in the current shell's job table, and avoid receiving SIGHUP when the shell exits. Which sequence is appropriate?

48 A pipeline consists of several processes in process group 8120. The administrator wants to send SIGTERM to every process in that group without relying on individual PIDs. Which command is correct?

49 A server reports a load average of 40, yet CPU utilization remains near 10%. ps shows many processes in state D. Which interpretation is most accurate?

50 A systemd unit applies firewall rules through a command that exits successfully. The unit must remain logically active afterward so that systemctl stop can invoke ExecStop to remove the rules. Which unit settings are appropriate?

51 systemctl is-enabled helper.service reports static, but helper.service starts during every boot. What is the most likely explanation?

52 A service must be stopped immediately and prevented from being started manually or as a dependency after future reboots. Which command provides the strongest systemd-level prohibition?

53 An SSH server must allow root to authenticate using public keys but must reject password and keyboard-interactive authentication for root. Which sshd_config directive best expresses this policy?

54 After a server is rebuilt, SSH reports that its host key has changed. What is the safest administrative response?

55 A public key in authorized_keys must run only /usr/local/bin/report and must not permit a PTY, agent forwarding, X11 forwarding, or TCP forwarding. Which entry prefix is most suitable on a modern OpenSSH server?

56 An administrator has added several Match blocks to sshd_config. Before reloading SSH, which commands should be used to check syntax and inspect the effective configuration for user backup connecting from 192.0.2.25?

57 A program launched by a systemd service writes only to standard output and standard error. The system uses systemd-journald and an rsyslog configuration that loads imjournal. Which path best describes how the message can reach a traditional log file?

58 An rsyslog rule uses the selector authpriv.warning. Which message matches this selector under standard syslog severity semantics?

59 A host currently keeps journal data only under /run/log/journal. Which change most reliably enables storage across reboots and prepares the journal directory with appropriate system-managed attributes?

60 After a virtual machine resumes, its clock is eight minutes behind and time-sensitive authentication is failing. chronyd is running, but normal correction would slew the clock too slowly. Which command requests an immediate correction while retaining chrony synchronization?