Permissions and Ownership

Question 1

Which of the following chmod commands adds execute permission for only the file owner?

🔘 Options
A. a+x
B. u+x
C. g+x
D. o+x

Answer 1

✅ Correct Answer
B. u+x

💡 Explanation
A. ❌ Adds execute for all users (user, group, others).
B. ✅ Correct — u+x adds execute permission for the file owner (user) only.
C. ❌ Affects only the group.
D. ❌ Affects only others.

Question 2

Which of the following commands removes write permission from others without affecting the file owner or group?

🔘 Options
A. chmod a-w file.txt
B. chmod u-w file.txt
C. chmod o-w file.txt
D. chmod g-w file.txt

Answer 2

✅ Correct Answer
C. chmod o-w file.txt

💡 Explanation
A. ❌ Removes write permission from everyone, including the user.
B. ❌ Removes write from the owner.
C. ✅ Correct — removes write permission from others only.
D. ❌ Affects only the group.

Question 3

If you want every user (owner, group, and others) to have execute permission on a file, which command should you use?

🔘 Options
A. u+x
B. g+x
C. o+x
D. a+x

Answer 3

✅ Correct Answer
D. a+x

💡 Explanation
A. ❌ Adds execute only for the owner.
B. ❌ Adds execute for group only.
C. ❌ Adds execute for others only.
D. ✅ Correct — a+x gives execute permission to all users.

Question 4

What does the command chmod -R 755 /var/www/html do?

🔘 Options
A. Changes one file’s permissions only
B. Adds execute permission for the user
C. Recursively applies 755 permissions
D. Removes write permission from others

Answer 4

✅ Correct Answer
C. Recursively applies 755 permissions

💡 Explanation
A. ❌ -R indicates multiple files and directories, not a single file.
B. ❌ Only adding execute would use symbolic syntax.
C. ✅ Correct — -R recursively changes permissions for all items inside the directory.
D. ❌ This command doesn’t specifically remove permissions.

Question 5

How can you display the default permissions for new files in a symbolic (human-readable) format?

🔘 Options
A. chmod -S
B. umask
C. umask -S
D. ls -l

Answer 5

✅ Correct Answer
C. umask -S

💡 Explanation
A. ❌ chmod doesn’t show default permissions.
B. ❌ Shows numeric format, not symbolic.
C. ✅ Correct — umask -S displays symbolic default permission mask.
D. ❌ Lists permissions of existing files.

Question 7

Which chmod option will suppress error messages if a file doesn’t exist?

🔘 Options
A. -v
B. -c
C. -f
D. -R

Answer 7

✅ Correct Answer
C. -f

💡 Explanation
A. ❌ -v provides verbose output; it does not suppress errors.
B. ❌ -c shows changes, but doesn’t hide errors.
C. ✅ Correct — -f stands for “force” and suppresses error messages.
D. ❌ -R makes the command recursive.

Question 8

Which chmod option will show output only if a file’s permissions are actually changed?

🔘 Options
A. -v
B. -f
C. -R
D. -c

Answer 8

✅ Correct Answer
D. -c

💡 Explanation
A. ❌ -v always prints output, even if nothing changed.
B. ❌ -f suppresses output entirely.
C. ❌ -R is for recursive changes, not output behavior.
D. ✅ Correct — -c prints only if the permission was actually changed.

Question 9

What is the key difference between chmod and umask?

🔘 Options
A. Both modify current permissions
B. umask edits current permissions
C. chmod changes default permissions for new files
D. chmod modifies existing files, umask sets defaults

Answer 9

✅ Correct Answer
D. chmod modifies existing files, umask sets defaults

💡 Explanation
A. ❌ Only chmod modifies existing permissions.
B. ❌ umask defines default permissions for new files, not current ones.
C. ❌ chmod does not affect new files.
D. ✅ Correct — chmod affects current files; umask sets default creation rules.

Question 10

Which command configures the default permission mask for newly created files and directories?

🔘 Options
A. chmod
B. ls -l
C. umask
D. stat

Answer 10

✅ Correct Answer
C. umask

💡 Explanation
A. ❌ chmod affects only existing files.
B. ❌ ls -l shows file permissions, but doesn’t set defaults.
C. ✅ Correct — umask sets default permission rules for new files.
D. ❌ stat is used to view detailed file metadata.

Question 11

If you want to print a message every time you attempt to change file permissions — even if the permissions don’t change — which chmod option should you use?

🔘 Options
A. -c
B. -R
C. -v
D. -f

Answer 11

✅ Correct Answer
C. -v

💡 Explanation
A. ❌ -c shows output only when changes occur.
B. ❌ -R affects directories recursively but doesn’t control output.
C. ✅ Correct — -v stands for “verbose” and prints messages regardless of change.
D. ❌ -f suppresses output entirely.

Question 12

When a new file is created in Linux, the system starts with a default permission value. What is the default permission for files before applying the umask?

🔘 Options
A. 777 (rwxrwxrwx)
B. 666 (rw-rw-rw-)
C. 600 (rw——-)
D. 644 (rw-r–r–)

Answer 12

✅ Correct Answer
B. 666 (rw-rw-rw-)

💡 Explanation
A. ❌ 777 is the default for directories, not files.
B. ✅ Correct — files start with 666 so they are readable and writable, but not executable by default.
C. ❌ 600 is a possible result after applying a strict umask.
D. ❌ 644 is a common final result, not the default base.

Question 13

Which of the following best describes the role of umask in Linux file creation?

🔘 Options
A. It sets exact permissions for each new file
B. It adds permissions to the default mode
C. It subtracts from the default permissions to get the final mode
D. It applies executable permission to new scripts

Answer 13

✅ Correct Answer
C. It subtracts from the default permissions to get the final mode

💡 Explanation
A. ❌ umask doesn’t set; it modifies.
B. ❌ It subtracts, not adds.
C. ✅ Correct — umask subtracts from the default (666 for files, 777 for dirs).
D. ❌ It doesn’t automatically add execute permission.

Question 14

If the umask value is set to 0022, what will be the final permission for a newly created directory?

🔘 Options
A. 777
B. 755
C. 775
D. 644

Answer 14

✅ Correct Answer
B. 755

💡 Explanation
A. ❌ 777 is the base, not the final result.
B. ✅ Correct — 777 - 022 = 755 → rwxr-xr-x.
C. ❌ 775 is used with umask 0002.
D. ❌ 644 is for files, not directories.

Question 15

Which of the following explains why new files don’t have execute (x) permission by default?

🔘 Options
A. umask always strips execute permission
B. Files don’t need execute permission
C. For security, the system prevents automatic execution
D. It depends on the filesystem used

Answer 15

✅ Correct Answer
C. For security, the system prevents automatic execution

💡 Explanation
A. ❌ umask may allow execute, but files still won’t get it.
B. ❌ Scripts and binaries do need execute, but must request it.
C. ✅ Correct — Linux avoids giving execute by default for safety.
D. ❌ It’s a system-level behavior, not filesystem-dependent.

Question 16

What would be the final permission for a newly created file if umask is set to 0077?

🔘 Options
A. rw-r–r–
B. rw-rw-rw-
C. rw——-
D. rwx——

Answer 16

✅ Correct Answer
C. rw——-

💡 Explanation
A. ❌ This would happen with umask 0022.
B. ❌ This is the starting point (666), not the result.
C. ✅ Correct — 666 - 077 = 600 → rw——-.
D. ❌ That’s for directories, not files.

Question 17

Which umask value results in files that are only accessible by the owner and completely private?

🔘 Options
A. 0000
B. 0022
C. 0077
D. 0777

Answer 17

✅ Correct Answer
C. 0077

💡 Explanation
A. ❌ 0000 makes files open to everyone.
B. ❌ Allows group and others to read files.
C. ✅ Correct — 0077 removes all permissions for group and others.
D. ❌ Invalid; umask values only go up to 0777.

Question 18

When you run umask -S in the terminal, what type of output should you expect?

🔘 Options
A. Numeric value like 0022
B. Script name
C. Symbolic format like u=rwx,g=rx,o=rx
D. File listing with permissions

Answer 18

✅ Correct Answer
C. Symbolic format like u=rwx,g=rx,o=rx

💡 Explanation
A. ❌ That’s the output from just umask.
B. ❌ That’s unrelated to umask.
C. ✅ Correct — umask -S shows symbolic permission settings.
D. ❌ ls -l provides file listings, not umask.

Question 19

Which of the following best describes the permission outcome of a newly created folder when umask is set to 0077?

🔘 Options
A. rwxr-xr-x
B. rwx——
C. rwxrwxrwx
D. rw——-

Answer 19

✅ Correct Answer
B. rwx——

💡 Explanation
A. ❌ That’s the result with umask 0022.
B. ✅ Correct — 777 - 077 = 700 → rwx——.
C. ❌ That’s the base before umask.
D. ❌ That’s for files, not folders.

Question 20

After setting umask 0077, you create a file using touch myfile.txt. What permissions should you expect?

🔘 Options
A. rw-r–r–
B. rw——-
C. rwx——
D. rwxrwxrwx

Answer 20

✅ Correct Answer
B. rw——-

💡 Explanation
A. ❌ That would happen with umask 0022.
B. ✅ Correct — 666 - 077 = 600 → rw——-.
C. ❌ Execute is not given to files by default.
D. ❌ That’s the starting value, not final permissions.

Question 21

Which of the following statements about dotfiles (e.g., .bashrc) is true?

🔘 Options
A. They are always executable files
B. They are usually system logs
C. They are typically hidden configuration or script files
D. They are only used by root users

Answer 21

✅ Correct Answer
C. They are typically hidden configuration or script files

💡 Explanation
A. ❌ Not all dotfiles are executable.
B. ❌ Log files are not usually dotfiles.
C. ✅ Correct — dotfiles like .bashrc are usually hidden scripts or configs.
D. ❌ Regular users have dotfiles too (e.g., .profile, .bash_history).

Question 22

Which of the following commands would you use to change both the owner and group of a file named report.txt to alice and devs respectively?

🔘 Options
A. chgrp alice:devs report.txt
B. chown alice devs report.txt
C. chown alice:devs report.txt
D. chgrp alice devs report.txt

Answer 22

✅ Correct Answer
C. chown alice:devs report.txt

💡 Explanation
A. ❌ chgrp only changes the group, and syntax is incorrect here.
B. ❌ chown with two separate arguments is invalid.
C. ✅ Correct — chown user:group filename changes both owner and group.
D. ❌ chgrp doesn’t support changing the user.

Question 23

You want to change only the group of a file without modifying the file’s current owner. Which chown syntax would you use?

🔘 Options
A. chown user: file.txt
B. chown :group file.txt
C. chown file.txt :group
D. chown group: file.txt

Answer 23

✅ Correct Answer
B. chown :group file.txt

💡 Explanation
A. ❌ Syntax is incomplete — it implies a group is missing.
B. ✅ Correct — using chown :group file.txt changes just the group.
C. ❌ Syntax is reversed and invalid.
D. ❌ group: format isn’t valid for chown.

Question 24

Which command is specifically designed to change the group ownership of a file only?

🔘 Options
A. chmod
B. chown
C. chgrp
D. umask

Answer 24

✅ Correct Answer
C. chgrp

💡 Explanation
A. ❌ chmod changes permissions, not ownership.
B. ❌ chown can change both user and group, but is not exclusive to group.
C. ✅ Correct — chgrp is dedicated to group ownership changes.
D. ❌ umask controls default permissions, not ownership.

Question 25

You run the following command: sudo chown :admins file.txt. What does it do? 🔘 Options A. Changes the owner and group to admins B. Only changes the group to admins C. Only changes the owner to admins D. Deletes the current group

Answer 25

✅ Correct Answer B. Only changes the group to admins 💡 Explanation A. ❌ Owner is unchanged — only group is modified. B. ✅ Correct — chown :group modifies only the group. C. ❌ The owner is not affected unless specified. D. ❌ chown never deletes anything.

Question 26

You run the following command: sudo chgrp admins myfile.txt. What will it change? 🔘 Options A. The owner of myfile.txt B. The file permissions C. The group associated with myfile.txt D. Nothing — the command is invalid

Answer 26

✅ Correct Answer C. The group associated with myfile.txt 💡 Explanation A. ❌ chgrp doesn't change the user owner. B. ❌ chmod is used to change permissions. C. ✅ Correct — chgrp changes group ownership only. D. ❌ The command is valid.

Question 27

What is the result of running chown mousa:admins file.txt? 🔘 Options A. Changes only the file owner to mousa B. Changes only the group to admins C. Changes both owner to mousa and group to admins D. Changes file permissions to 777

Answer 27

✅ Correct Answer C. Changes both owner to mousa and group to admins 💡 Explanation A. ❌ That would be chown mousa file.txt. B. ❌ That would be chown :admins file.txt. C. ✅ Correct — both values are modified. D. ❌ Ownership changes don’t affect file permissions.

Question 28

If a file shows this output: -rw-r--r-- 1 mousa devs myfile.txt, which field indicates the group owner? 🔘 Options A. -rw-r--r-- B. 1 C. mousa D. devs

Answer 28

✅ Correct Answer D. devs 💡 Explanation A. ❌ This is the permission string. B. ❌ This shows the link count. C. ❌ This is the file owner. D. ✅ Correct — group ownership is the second name after the owner.

Question 29

You want to make a file belong to the data group without affecting the current user owner. What’s the simplest way to do that? 🔘 Options A. chown data file.txt B. chgrp data file.txt C. chmod data file.txt D. chown : file.txt

Answer 29

✅ Correct Answer B. chgrp data file.txt 💡 Explanation A. ❌ chown expects a username or user:group format. B. ✅ Correct — chgrp is designed for changing only the group. C. ❌ chmod changes permissions, not ownership. D. ❌ Syntax is incomplete.

Question 30

Which command is equivalent to chown :admins file.txt in function? 🔘 Options A. chmod +x file.txt B. umask 0022 C. chgrp admins file.txt D. chown file.txt :admins

Answer 30

✅ Correct Answer C. chgrp admins file.txt 💡 Explanation A. ❌ Adds execute permission, unrelated to ownership. B. ❌ Sets default permissions, not ownership. C. ✅ Correct — both change only the group. D. ❌ Incorrect syntax.

Question 31

Why might someone use chgrp instead of chown when modifying file ownership? 🔘 Options A. chgrp is faster and changes both owner and group B. chgrp is simpler for group changes and doesn't affect the user C. chgrp also modifies file permissions D. chgrp can only be used by the root user

Answer 31

✅ Correct Answer B. chgrp is simpler for group changes and doesn't affect the user 💡 Explanation A. ❌ chgrp only changes the group, not both. B. ✅ Correct — it’s simpler and avoids modifying the user owner. C. ❌ Ownership and permissions are separate. D. ❌ Regular users can use chgrp on files they own.

Question 32

Which of the following best explains why the passwd command allows a normal user to update their password, even though the /etc/shadow file is owned by root? 🔘 Options A. It uses ACLs to grant access B. It runs as a background service C. It has the SUID bit set D. It’s part of the sudoers group

Answer 32

✅ Correct Answer C. It has the SUID bit set 💡 Explanation A. ❌ ACLs control access, but not ownership-based execution. B. ❌ passwd is not a service. C. ✅ Correct — passwd has the SUID bit set, so it runs with root’s privileges. D. ❌ The user doesn’t need to be a sudoer to use passwd.

Question 33

What is the primary security benefit of using the SUID bit on certain trusted programs? 🔘 Options A. It encrypts the file during execution B. It allows full root access to users C. It provides just enough privilege to complete a specific task D. It replaces the need for sudo entirely

Answer 33

✅ Correct Answer C. It provides just enough privilege to complete a specific task 💡 Explanation A. ❌ SUID doesn’t encrypt files. B. ❌ It doesn’t give full root access. C. ✅ Correct — it gives temporary elevated rights for a narrow task. D. ❌ SUID is for specific programs, not general privilege escalation.

Question 34

Which of the following users can set the SUID bit on a file owned by root? 🔘 Options A. Any user who owns the file B. Only users in the wheel group or sudoers file C. Any member of the file’s group D. No one — only root can do tha

Answer 34

✅ Correct Answer B. Only users in the wheel group or sudoers file 💡 Explanation A. ❌ File owners can’t set SUID unless they are root. B. ✅ Correct — SUID on root-owned files can only be set by users with sudo privileges. C. ❌ Group members don’t have that power. D. ❌ Sudoers can also set it.

Question 35

What happens when a regular user runs a file with the SUID bit set and the file is owned by root? 🔘 Options A. The file runs with the user's regular permissions B. The file runs with the root user's permissions C. The user becomes root until logout D. The file becomes writable by everyone

Answer 35

✅ Correct Answer B. The file runs with the root user's permissions 💡 Explanation A. ❌ That’s standard behavior without SUID. B. ✅ Correct — the file executes with the owner's (root’s) privileges. C. ❌ SUID only elevates during execution, not system-wide. D. ❌ SUID doesn’t affect file writability.

Question 36

What does the SGID bit do when applied to a directory? 🔘 Options A. Makes the directory executable B. Prevents files from being deleted C. Forces all new files to inherit the directory’s group D. Locks the directory to the owner

Answer 36

✅ Correct Answer C. Forces all new files to inherit the directory’s group 💡 Explanation A. ❌ Executability is unrelated. B. ❌ That’s the sticky bit. C. ✅ Correct — SGID on directories enforces group inheritance. D. ❌ Group, not ownership, is affected.

Question 37

What does chmod 2775 /shared do? 🔘 Options A. Applies sticky bit and 775 permissions B. Adds the SGID bit and sets standard permissions C. Sets the directory as read-only D. Grants execute permissions to everyone

Answer 37

✅ Correct Answer B. Adds the SGID bit and sets standard permissions 💡 Explanation A. ❌ Sticky bit uses 1###. B. ✅ Correct — 2 = SGID, and 775 = rwxrwxr-x. C. ❌ It allows writing (7 includes write). D. ❌ Execute permissions are limited by the x bits.

Question 38

How can a user remove the SUID or SGID bit from a file? 🔘 Options A. Use chattr -i B. Use chmod -s C. Use lsattr -r D. Use chown to change owner

Answer 38

✅ Correct Answer B. Use chmod -s 💡 Explanation A. ❌ chattr manages file attributes, not permission bits. B. ✅ Correct — chmod -s removes special permissions like SUID and SGID. C. ❌ lsattr just lists attributes. D. ❌ Changing ownership won’t remove special bits.

Question 39

Which of the following statements best describes the sticky bit? 🔘 Options A. Prevents any write operation in a directory B. Allows only the file owner or root to delete files within a directory C. Grants full control of a file to the user D. Hides the directory from ls

Answer 39

✅ Correct Answer B. Allows only the file owner or root to delete files within a directory 💡 Explanation A. ❌ Writing is still allowed. B. ✅ Correct — sticky bit protects files from deletion by others. C. ❌ Control is based on permissions, not the sticky bit. D. ❌ Use dotfiles or chmod for hiding.

Question 40

Which attribute would you set to make a file immutable, meaning it cannot be modified, renamed, or deleted? 🔘 Options A. a B. c C. d D. i

Answer 40

✅ Correct Answer D. i 💡 Explanation A. ❌ a is for append-only. B. ❌ c means compressed. C. ❌ d excludes from backups. D. ✅ Correct — i makes a file immutable.

Question 41

What command would you use to view special file attributes like immutability or append-only? 🔘 Options A. ls -l B. lsattr C. getfacl D. chmod

Answer 41

✅ Correct Answer B. lsattr 💡 Explanation A. ❌ Shows standard permissions only. B. ✅ Correct — lsattr lists extended attributes. C. ❌ getfacl shows ACL entries. D. ❌ chmod changes permissions, doesn’t display them.

Question 42

Which command makes a file append-only, meaning content can be added but not changed or deleted? 🔘 Options A. chmod +a B. setfacl -m a C. chattr +a D. lsattr +a

Answer 42

✅ Correct Answer C. chattr +a 💡 Explanation A. ❌ That’s not a valid chmod flag. B. ❌ ACLs don’t define append-only behavior. C. ✅ Correct — chattr +a sets the append-only attribute. D. ❌ lsattr only lists attributes.

Question 43

You want to prevent accidental deletion of a config file like /etc/passwd. What’s the best approach? 🔘 Options A. Remove all permissions B. Use chmod 000 C. Set the immutable attribute with chattr +i D. Add a sticky bit to the file

Answer 43

✅ Correct Answer C. Set the immutable attribute with chattr +i 💡 Explanation A. ❌ That may prevent access, but not changes by root. B. ❌ Root can still change it. C. ✅ Correct — chattr +i locks the file completely. D. ❌ Sticky bit is for directories.

Question 44

Which of the following commands grants read access to john for report.txt without changing file ownership? 🔘 Options A. chmod o+r report.txt B. chown john report.txt C. setfacl -m u:john:r-- report.txt D. chattr +r report.txt

Answer 44

✅ Correct Answer C. setfacl -m u:john:r-- report.txt 💡 Explanation A. ❌ Affects all others, not specifically john. B. ❌ Transfers ownership. C. ✅ Correct — ACL allows custom user-specific access. D. ❌ No such +r option in chattr.

Question 45

Which of the following best describes the purpose of the mask line in an ACL? 🔘 Options A. It defines permissions for the owner B. It controls what permissions others have C. It limits maximum allowed ACL permissions for any user or group D. It hides ACL entries from view

Answer 45

✅ Correct Answer C. It limits maximum allowed ACL permissions for any user or group 💡 Explanation A. ❌ That’s user::. B. ❌ That’s other::. C. ✅ Correct — mask:: sets the upper boundary of ACL effectiveness. D. ❌ ACL entries are always visible.

Question 46

What does the command setfacl -b file.txt do? 🔘 Options A. Blocks access to the file B. Removes all ACL entries from the file C. Backs up the ACL settings D. Breaks the file’s permissions

Answer 46

✅ Correct Answer B. Removes all ACL entries from the file 💡 Explanation A. ❌ Does not block standard access. B. ✅ Correct — -b clears all ACLs, leaving only standard permissions. C. ❌ Use getfacl for exporting ACLs. D. ❌ Permissions are reset, not broken.

Question 47

What does the SGID permission on a directory do when a new file is created within it? 🔘 Options A. Sets the new file’s owner to root B. Gives write access to all users C. Ensures the file inherits the directory’s group D. Makes the file read-only

Answer 47

✅ Correct Answer C. Ensures the file inherits the directory’s group 💡 Explanation A. ❌ Ownership remains with the creator. B. ❌ Write access depends on file permissions. C. ✅ Correct — SGID on directories causes new files to inherit the directory's group. D. ❌ File permissions are not automatically set to read-only.

Question 48

If SGID is applied to a directory, which of the following scenarios would prevent it from working as expected? 🔘 Options A. The directory has 777 permissions B. The group assigned to the directory does not exist C. The user is a member of the assigned group D. The directory is owned by root

Answer 48

✅ Correct Answer B. The group assigned to the directory does not exist 💡 Explanation A. ❌ SGID can still work with 777 permissions. B. ✅ Correct — the group must exist and the user must belong to it for SGID to work as expected. C. ❌ This is required for SGID to work properly. D. ❌ Ownership doesn't prevent SGID behavior.

Question 49

Which command sets the sticky bit on a directory? 🔘 Options A. chmod 775 folder B. chmod +s folder C. chmod +t folder D. chattr +i folder

Answer 49

✅ Correct Answer C. chmod +t folder 💡 Explanation A. ❌ Does not set any special permissions. B. ❌ +s is for SUID or SGID. C. ✅ Correct — +t sets the sticky bit. D. ❌ chattr +i makes the file immutable.

Question 50

Which of the following does the sticky bit specifically prevent? 🔘 Options A. Users from modifying their own files B. Users from reading directory contents C. Users from deleting files they do not own D. Root from deleting files

Answer 50

✅ Correct Answer C. Users from deleting files they do not own 💡 Explanation A. ❌ Users can still modify their own files. B. ❌ Sticky bit doesn’t control read access. C. ✅ Correct — only file owners (or root) can delete files when sticky bit is set. D. ❌ Root can always delete files.

Question 51

What does the + sign at the end of a file’s permissions (e.g. drwxrwxrwx+) indicate? 🔘 Options A. The file is encrypted B. The file is immutable C. ACLs are applied D. SGID is set

Answer 51

✅ Correct Answer C. ACLs are applied 💡 Explanation A. ❌ Encryption is not indicated by +. B. ❌ Immutability shows with i via lsattr. C. ✅ Correct — + means the file has Access Control Lists applied. D. ❌ SGID shows as s in the group execute position.

Question 52

What does chattr +i filename do? 🔘 Options A. Gives the file read-only permissions B. Sets the file as immutable C. Compresses the file D. Adds execute permission

Answer 52

✅ Correct Answer B. Sets the file as immutable 💡 Explanation A. ❌ Read-only can still be removed by chmod. B. ✅ Correct — +i prevents any changes to the file, even by root. C. ❌ +c would be for compression. D. ❌ chmod +x adds execute permission.

Question 53

After setting the sticky bit on a shared directory, a user can still delete a file. What is the most likely reason? 🔘 Options A. The sticky bit was not set correctly B. The user owns the file C. The directory does not have write permissions D. The file has execute permissions

Answer 53

✅ Correct Answer B. The user owns the file 💡 Explanation A. ❌ Sticky bit might be correctly set. B. ✅ Correct — sticky bit prevents deletion only of others' files. C. ❌ This would prevent all changes. D. ❌ Execute permission does not affect deletion.

Question 54

What does the e character in lsattr output indicate? 🔘 Options A. The file is encrypted B. The file is owned by root C. The file uses extents for storage D. The file is executable

Answer 54

✅ Correct Answer C. The file uses extents for storage 💡 Explanation A. ❌ Not related to encryption. B. ❌ Ownership is shown by ls -l. C. ✅ Correct — e means extents, used for efficient storage on ext3/ext4. D. ❌ Execute permission is unrelated to this flag.

Question 55

Can the sticky bit be applied to regular files in modern Linux systems? 🔘 Options A. Yes, and it provides caching benefits B. Yes, but only on ext2 C. No, it's ignored when used on files D. No, it causes an error

Answer 55

✅ Correct Answer C. No, it's ignored when used on files 💡 Explanation A. ❌ That was true in older Unix versions. B. ❌ Still ignored in modern usage. C. ✅ Correct — sticky bit only applies to directories now. D. ❌ It doesn't error — it's just ignored.

Question 56

What is a key difference between using the sticky bit and the immutable bit? 🔘 Options A. Sticky bit restricts access to root B. Immutable bit allows renaming but not deletion C. Sticky bit is used in shared folders, immutable bit freezes files D. Sticky bit hides the file

Answer 56

✅ Correct Answer C. Sticky bit is used in shared folders, immutable bit freezes files 💡 Explanation A. ❌ Sticky bit doesn't restrict root. B. ❌ Immutable blocks renaming too. C. ✅ Correct — sticky protects shared files, immutable completely locks a file. D. ❌ Neither bit hides files.

Question 57

Which of the following permissions schemes will not show the effects of an ACL in a traditional ls -l listing? 🔘 Options A. rwxrwxrwx B. rwxrwxrwx+ C. rwxr-xr-x D. rwxrwx--x

Answer 57

✅ Correct Answer C. rwxr-xr-x 💡 Explanation A. ❌ This alone won’t show ACL, but it's valid. B. ❌ This does show ACL with the + sign. C. ✅ Correct — this shows standard permissions only, no ACL. D. ❌ Still standard permissions, no + means no ACL visible.

Question 58

How many groups can a file or directory have assigned by default in Linux (without ACLs)? 🔘 Options A. Unlimited B. Only one C. Two (primary and secondary) D. None

Answer 58

✅ Correct Answer B. Only one 💡 Explanation A. ❌ Only with ACLs can multiple be assigned. B. ✅ Correct — standard Linux permissions allow one group per file or directory. C. ❌ Users can have multiple groups, but files cannot. D. ❌ Every file must have a group.

Question 59

Which tool allows you to assign multiple group permissions to a file? 🔘 Options A. chmod B. chown C. setfacl D. chattr

Answer 59

✅ Correct Answer C. setfacl 💡 Explanation A. ❌ chmod only sets basic permissions. B. ❌ chown changes user and group ownership, not access. C. ✅ Correct — ACLs via setfacl let you assign multiple user/group rules. D. ❌ chattr sets attributes like immutability.

Question 60

Why didn’t adding write access to a group using setfacl change the visible permissions in ls -l? 🔘 Options A. ACL was applied incorrectly B. ACLs don’t affect ls -l output directly C. chmod must be rerun D. Only root can see ACLs

Answer 60

✅ Correct Answer B. ACLs don’t affect ls -l output directly 💡 Explanation A. ❌ ACL may have worked fine. B. ✅ Correct — ACLs are layered and only hinted at with a + sign in ls -l. C. ❌ ACL doesn’t require chmod to show. D. ❌ Any user can check ACLs with getfacl.

Question 61

If your file has the immutable attribute set, which of the following actions is possible? 🔘 Options A. Rename the file B. Delete the file C. Append content to the file D. None of the above

Answer 61

✅ Correct Answer D. None of the above 💡 Explanation A. ❌ Immutable prevents renaming. B. ❌ Immutable blocks deletion. C. ❌ Append requires the append-only attribute, not immutable. D. ✅ Correct — the file is completely locked.

Question 62

Which command is the safest and most direct way to remove a user from a group in Linux? 🔘 Options A. deluser username groupname B. usermod -r groupname username C. gpasswd -d username groupname D. groupdel username

Answer 62

✅ Correct Answer C. gpasswd -d username groupname 💡 Explanation A. ❌ deluser isn't available on all systems. B. ❌ usermod does not use -r for removing users from groups. C. ✅ Correct — gpasswd -d safely removes a user from a group. D. ❌ groupdel deletes the group itself.

Question 63

Which of the following commands shows the groups that a specific user belongs to? 🔘 Options A. id groupname B. whoami groups C. groups username D. ls -l /etc/group

Answer 63

✅ Correct Answer C. groups username 💡 Explanation A. ❌ id shows UID/GID, not all groups. B. ❌ This is an invalid combination. C. ✅ Correct — groups lists all groups a user belongs to. D. ❌ ls -l lists file metadata, not group membership.

Question 64

What does the getent command do in Linux? 🔘 Options A. Displays log files from systemd B. Edits file ownership and permissions C. Queries system databases like passwd, group, and hosts D. Scans the filesystem for broken permissions

Answer 64

✅ Correct Answer C. Queries system databases like passwd, group, and hosts 💡 Explanation A. ❌ That’s journalctl. B. ❌ chown and chmod are for permissions. C. ✅ Correct — getent retrieves entries from local and remote sources. D. ❌ No scanning is involved.

Question 65

Why is getent preferred over using cat /etc/passwd in modern Linux environments? 🔘 Options A. It sorts user accounts alphabetically B. It modifies group memberships C. It supports both local and network-based entries D. It provides a GUI for managing users

Answer 65

✅ Correct Answer C. It supports both local and network-based entries 💡 Explanation A. ❌ Sorting isn’t the goal. B. ❌ getent is read-only. C. ✅ Correct — it works with LDAP, NIS, and more, as well as local files. D. ❌ It’s a CLI tool, not GUI-based.

Question 66

What file does getent consult to determine which sources to query for users, groups, and hosts? 🔘 Options A. /etc/shadow B. /etc/nsswitch.conf C. /etc/sudoers D. /etc/login.defs

Answer 66

✅ Correct Answer B. /etc/nsswitch.conf 💡 Explanation A. ❌ That file stores passwords, not query logic. B. ✅ Correct — this config file defines the source order (files, LDAP, etc.). C. ❌ Manages sudo permissions, not lookup behavior. D. ❌ Controls user defaults, not data sources.

Question 67

Which command lists all users on a system using getent? 🔘 Options A. getent group B. getent passwd C. getent users D. getent shadow

Answer 67

✅ Correct Answer B. getent passwd 💡 Explanation A. ❌ Lists groups. B. ✅ Correct — getent passwd lists all user accounts. C. ❌ users is not a valid getent database. D. ❌ shadow contains sensitive password hashes, not user lists.

Question 68

How can you check which users are members of the CryptoDept group using getent? 🔘 Options A. getent passwd CryptoDept B. getent group CryptoDept C. groups CryptoDept D. cat /etc/sudoers | grep CryptoDept

Answer 68

✅ Correct Answer B. getent group CryptoDept 💡 Explanation A. ❌ This queries user info, not group membership. B. ✅ Correct — shows group info including its members. C. ❌ groups is for checking a user’s groups, not a group’s users. D. ❌ Irrelevant to general group membership.

Question 69

What would the command getent passwd emusk return? 🔘 Options A. Group memberships of emusk B. Login session info for emusk C. The full passwd entry for emusk D. A list of emusk’s shell commands

Answer 69

✅ Correct Answer C. The full passwd entry for emusk 💡 Explanation A. ❌ Use groups emusk for that. B. ❌ Use w or who for login sessions. C. ✅ Correct — shows UID, GID, home directory, and shell. D. ❌ Shell history is not part of this output.

Question 70

Which of the following getent commands would show how localhost is resolved? 🔘 Options A. getent host localhost B. getent hosts localhost C. getent passwd localhost D. getent group localhost

Answer 70

✅ Correct Answer B. getent hosts localhost 💡 Explanation A. ❌ Wrong syntax. B. ✅ Correct — queries hostname resolution data from /etc/hosts and DNS. C. ❌ Queries users, not hosts. D. ❌ Queries groups.

Question 71

What is a primary advantage of using getent in an LDAP-integrated environment? 🔘 Options A. It allows changing LDAP passwords B. It provides user login statistics C. It retrieves user/group information from centralized directories D. It runs faster than ls

Answer 71

✅ Correct Answer C. It retrieves user/group information from centralized directories 💡 Explanation A. ❌ Password changes require dedicated tools. B. ❌ Use last or w for that. C. ✅ Correct — getent is LDAP-aware and can pull data from network sources. D. ❌ Speed isn't the main benefit.