Day 5 - System Task Mock Exam + Error Notebook: Cementing It with 12 Questions

📌 Key Points

• We review this week's entire scope (command options, configuration files, disk/LVM/permissions, processes/scheduling/systemd) with a 12-question mock exam.
• Task-style questions are a battle of whether you can instantly answer "which command / option / path does this task need?"
• Don't just look at the answers; read the explanations of why the other choices are wrong to fill in the points where you get confused.
• A good number of questions turn on telling "works now" from "permanent setting" - start/mount/at versus enable/fstab/crontab.
• For any question you get wrong, go back to the corresponding Day's text and memorize the tables again.

Exam Strategy in One Line

• Octal permissions: rwx=7, rw-=6, r-x=5, r--=4 - you should be able to convert instantly, as in chmod 755=rwxr-xr-x.
• Recursion is uppercase -R (chmod/chown), while grep recursion is -r.
• kill -9=forced termination, kill -1 (HUP)=re-read configuration, kill -15=graceful termination (default).
• passwd 7 fields / shadow 9 fields / fstab 6 fields - you need to know the field counts and order.
• Disk: fdisk → mkfs → mount → fstab. LVM: pvcreate → vgcreate → lvcreate, and expansion is lvextend + resize2fs.
• Special permissions: SetUID 4000, SetGID 2000, Sticky 1000.
• enable=start at boot, start=start now - the two are separate.

📖 Glossary

• Task-style question : A format in the second-round practical exam where you write commands, options, and paths directly. It asks "what do you type", not for a conceptual explanation.
• Octal permissions : Notation that converts rwx to numbers. Since r=4, w=2, x=1, rwx=7, rw-=6, r-x=5, r--=4.
• Recursive option : An option that applies to subdirectories all at once. For chmod and chown it is uppercase -R.
• SIGHUP(1) : A signal that tells a daemon to "re-read its configuration file". Used to reload without a restart.
• umask : The bits removed from the default permissions of newly created files and directories. Files are 666−umask, directories 777−umask.
• resize2fs : The command that, after growing an LV, matches the actual size of an ext2/3/4 filesystem. For xfs, use xfs_growfs.
• vgextend : The LVM command that adds a new physical volume (PV) to a volume group to grow the storage pool.
• enable --now : The systemctl option that does autostart registration (enable) and immediate start (start) at once.
• daemon-reload : The command that makes systemd pick up changes after you edit a systemd unit file. If you skip it, your edits are ignored.

📝 Practice Questions

Click a choice to reveal the answer and explanation.

Question 1

Which command changes, in one go, the permissions of all files and directories under the directory /project to rwxr-xr-x?

• Achmod -r 755 /project
• Bchmod -R 755 /project
• Cchmod 755 -a /project
• Dchmod 644 -R /project

Question 2

Which command correctly finds only regular files larger than 100MB under the /data directory?

• Afind /data -size +100M -type f
• Bfind /data -size -100M -type d
• Cgrep -size +100M /data
• Dfind /data -size 100M -type l

Question 3

Which command sends SIGHUP so that a daemon re-reads its configuration file without restarting?

• Akill -9 PID
• Bkill -15 PID
• Ckill -1 PID
• Dkill -19 PID

Question 4

What is the absolute path of the file that stores a user account's UID, home directory, and login shell information?

• A/etc/shadow
• B/etc/group
• C/etc/passwd
• D/etc/login.defs

Question 5

What does the 6th field of /etc/fstab mean, and what value goes in for the root filesystem?

• Adump backup flag, 0
• Bfsck check order, 1
• Cmount options, defaults
• Dfilesystem type, ext4

Question 6

You want to format the new partition /dev/sdc1 as xfs and then mount it on /srv. Which is the correct format command?

• Amount -t xfs /dev/sdc1 /srv
• Bmkfs -t xfs /dev/sdc1
• Cfdisk -t xfs /dev/sdc1
• Dxfs_growfs /dev/sdc1

Question 7

Which command adds the new physical volume /dev/sdd to the volume group vg01 in LVM to increase capacity?

• Alvextend vg01 /dev/sdd
• Bpvcreate vg01 /dev/sdd
• Cvgextend vg01 /dev/sdd
• Dvgcreate vg01 /dev/sdd

Question 8

After growing a logical volume with lvextend, which command extends the actual capacity of the ext4 filesystem?

• Axfs_growfs
• Bresize2fs
• Cmkfs.ext4
• Dvgextend

Question 9

What is the permission of a newly created directory when the umask value is 077?

• A755
• B700
• C644
• D600

Question 10

Which command sets up a shared directory like /tmp so that anyone can create files but can delete only the files they created?

• Achmod 4777 /tmp
• Bchmod 2777 /tmp
• Cchmod 1777 /tmp
• Dchmod 0777 /tmp

Question 11

Which entry registers /backup.sh in crontab to run every Sunday at 4 AM?

• A0 4 * * 0 /backup.sh
• B4 0 * * 7 /backup.sh
• C0 4 7 * * /backup.sh
• D0 4 * * 1 /backup.sh

Question 12

Which command starts the httpd service immediately and, at the same time, registers it to start automatically at boot, all in one go?

• Asystemctl start httpd
• Bsystemctl enable httpd
• Csystemctl enable --now httpd
• Dsystemctl restart --now httpd

Error Notebook: Summary of Commonly Missed Traps

We regroup the points that most often cause confusion in this week's 12 questions.

💡 Wrap-up: Half of the task-style questions turn on separating "works now" from "permanent setting". If the scenario contains "even after boot", "even after a reboot", or "periodically", pick a persistence command such as enable, /etc/fstab, crontab, or sysctl -p. Conversely, for "now" or "once", it is start, mount, or at.

⚠️ Trap roundup: ① The owner:group separator in chown is the colon (:). ② grep -v selects lines that do not match. ③ find -mtime +7 means older than 7 days. ④ If you skip resize2fs/xfs_growfs after extending an LV, the capacity is not reflected. ⑤ Forgetting daemon-reload after editing a unit file. These five are the regular point-loss spots in the practical exam.

If you got any questions wrong, go back to the Day matching the question number - questions 1 and 2 are Day 1 (command options), 4 and 5 are Day 2 (configuration files), 6 to 10 are Day 3 (disk, LVM, permissions), and 11 and 12 are Day 4 (process, systemd). Rewrite the tables by hand and repeat until the commands, options, and paths come out automatically, and the system task section of the second-round practical exam is well within your reach.