MODULE 17- Owners and permissions

Question 1

Which user is the owner of a file by default when it’s created?

Answer 1

The user who created the file

Question 2

Which group becomes the group owner of a file by default when a user creates it?

Answer 2

The user’s primary group

Question 3

Which command should be used to check which groups you can switch to using newgrp?

Answer 3

groups

Question 3

What determines the ownership of a file internally in the operating system?

Answer 3

→ UID for user ownership and GID for group ownership

Question 4

Which command is used to verify the current user and their group memberships, including UID and GID?

Answer 4

id

Question 5

Which situation is indicated when a user and their primary group share the same name and numeric ID?

Answer 5

→ The user is in a User Private Group (UPG)

Question 6

Which command is used to create an empty file that will automatically be owned by the current user and group?

Answer 6

touch

Question 7

Which part of this command output represents the user and group owner: -rw-rw-r–. 1 sysadmin sysadmin 0 Oct 21 10:18?

Answer 7

→ The first ‘sysadmin’ is the user owner, the second ‘sysadmin’ is the group owner

Question 8

Which command reveals all files, including hidden ones, along with their ownership and permissions?

Answer 8

→ ls -la

Question 9

Which command is used by a user to change their current primary group during a session?

Answer 9

→ newgrp group_name

Question 10

What must be true for a user to successfully switch to another group using newgrp?

Answer 10

→ The user must already be a member of that group

Question 11

Which command shows the current primary group and all group memberships with UID/GID details?

Answer 11

id

Question 12

After using newgrp research, which group will new files belong to by default?

Answer 12

→ The research group

Question 13

How can a user return to their original primary group after using newgrp?

Answer 13

→ By running the exit command to leave the subshell

Question 13

Which command is used by administrators to permanently change a user’s primary group?

Answer 13

→ usermod -g groupname username

Question 14

Which command is used to change the group owner of a file?

Answer 14

→ chgrp group_name file

Question 15

What is required for a non-root user to successfully change a file’s group using chgrp?

Answer 15

→ The user must own the file and the target group must be one they are a member of

Question 16

What does this command do: chgrp research sample?

Answer 16

→ Changes the group ownership of the file sample to the research group

Question 17

Which option allows chgrp to change the group of all files and subdirectories in a directory?

Answer 17

→ -R (recursive)

Question 18

What does the command chgrp -R development test_dir do?

Answer 18

→ Changes the group owner of test_dir and everything inside it to development

Question 19

Which command displays a file’s ownership, permissions, and other detailed metadata?

Answer 19

stat

Question 20

Which command is used to change the user owner of a file or directory?

Answer 20

chown

Question 21

Can a regular user change the user ownership of their own file to another user?

Answer 21

→ No, only root can do this

Question 22

What does the command chown jane /tmp/filetest1 do?

Answer 22

→ Changes the user owner of /tmp/filetest1 to jane, keeping the group unchanged

Question 23

Which symbol can separate user and group in the chown command?

Answer 23

→ Either a colon (:) or a period (.)

Question 23

How do you change both the user and group ownership using chown?

Answer 23

→ chown user:group file or chown user.group file

Question 24

What does chown jane:users /tmp/filetest2 do?

Answer 24

→ Changes the user to jane and the group to users for /tmp/filetest2

Question 25

Which command structure allows a regular user to use chown like chgrp to change just the group?

Answer 25

→ chown :group file or chown .group file

Question 26

What is the effect of the command chown .users /tmp/filetest1 when run by user jane?

Answer 26

→ Changes the group owner of the file to users, keeping the user as jane

Question 27

Which character indicates a regular file in ls -l output?

Answer 27

-

Question 27

Which character represents a directory in ls -l output?

Answer 27

d

Question 28

Which file type is indicated by the character l?

Answer 28

→ A symbolic link that points to another file

Question 29

Which file type character indicates a block device file?

Answer 29

b

Question 30

What file type is indicated by the character c in ls -l output?

Answer 30

→ A character device file

Question 30

What does the file type character p represent?

Answer 30

→ A pipe file, used for communication between processes

Question 31

What does the character s represent in the first position of ls -l output?

Answer 31

→ A socket file used for two-way process communication

Question 32

What do characters 2–4 represent in the permissions string?

Answer 32

→ User owner's read, write, and execute permissions

Question 33

What do characters 5–7 represent in the permissions string?

Answer 33

→ Group owner's permissions

Question 34

What do characters 8–10 represent in the permissions string?

Answer 34

→ Others' (world's) permissions

Question 35

Which directory is represented by drwxr-xr-x. 17 root root 4096 23:38 /?

Answer 35

→ The root (/) directory

Question 36

Which file is represented by -rwxr-xr--. 1 bob bob 100 21:08 /data/abc.txt?

Answer 36

→ The file abc.txt located inside /data

Question 36

True or False: Based on the following information the user bob can successfully execute the following command: more /data/abc.txt? drwxr-xr-x. 17 root root 4096 23:38 / dr-xr-x- -x. 10 root root 128 03:38 /data -rwxr-xr- -. 1 bob bob 100 21:08 /data/abc.txt

Answer 36

True – Bob can execute more /data/abc.txt because he has execute permission on the /data directory and read permission on the file.

Question 36

Based on the following information, who can delete the /data/abc.txt file? drwxr-xr-x. 17 root root 4096 23:38 / drwxrw-rw-. 10 root root 128 03:38 /data -rwxr-xr--. 1 bob bob 100 21:08 /data/abc.txt

Answer 36

Only the root user. Only users with write and execute permissions on the parent directory (/data) can delete its contents — and only root has that power here.

Question 37

True or False: Based on the following information the user bob can successfully execute the following command: more /data/abc.txt? drwxr-xr-x. 17 root root 4096 23:38 / dr-xr-x---. 10 sue payroll 128 03:38 /data -rwxr-xr--. 1 bob bob 100 21:08 /data/abc.txt

Answer 37

Not enough information to determine. Bob does not have execute permission on /data, so he cannot access any files inside it — even if he owns abc.txt. membership in payroll determines whether bob has that crucial execute (x) access.

Question 37

True or False: Based on the following information the user bob can successfully execute the following command: more /data/abc.txt? drwxr-xr-x. 17 root root 4096 23:38 / dr-xr-x- -x. 10 root root 128 03:38 /data -rwxr-xr- -. 1 bob bob 100 21:08 /data/abc.txt

Answer 37

True. bob has execute permission on /data and read permission on the file.

Question 38

Based on the following information, who can use the ls command to display the contents of the /data directory (ls /data)? drwxr-xr-x. 17 root root 4096 23:38 / drwxr-xr--. 10 root root 128 03:38 /data -rwxr-xr--. 1 bob bob 100 21:08 /data/abc.txt

Answer 38

All users. For a user to view the contents of a directory with ls, they only need the read (r) permission on that directory. However, they also need the execute (x) permission on all parent directories, in this case, /, to traverse through the path to get to /data.

Question 39

In chmod ug+x,o-r abc.txt, what does o-r do?

Answer 39

→ Removes read permission from others

Question 39

In chmod ug+x,o-r abc.txt, what does ug+x do?

Answer 39

→ Adds execute permission to the user owner and group owner

Question 40

Which chmod command would remove all permissions from group and others, while keeping user owner permissions unchanged?

Answer 40

→ chmod go= abc.txt

Question 41

What is the effect of the command chmod u=rx abc.txt?

Answer 41

→ Sets the user owner's permissions to read and execute only, removing write

Question 42

Which command can show you the permissions of a file using both symbolic and octal methods?

Answer 42

The stat command

Question 43

Which command is used to change permissions?

Answer 43

The chmod command

Question 44

Which command is used to determine or display the default permissions mask for newly created files and directories?

Answer 44

umask

Question 44

What are the maximum default permissions for a newly created file before applying umask?

Answer 44

→ rw-rw-rw- (octal: 666)

Question 45

What are the maximum default permissions for a newly created directory before applying umask?

Answer 45

→ rwxrwxrwx (octal: 777)

Question 45

If umask is 0022, what would be the default permissions for a newly created directory?

Answer 45

→ rwxr-xr-x

Question 46

If umask is 0022, what would be the default permissions for a newly created file?

Answer 46

→ rw-r--r--

Question 47

True or False: Based on the following information the user bob can successfully execute the following command: more /data/abc.txt? drwxr-xr-x. 17 root root 4096 23:38 / dr-xr-x---. 10 bob bob 128 03:38 /data ----rw-rwx. 1 bob bob 100 21:08 /data/abc.txt

Answer 47

False. Bob cannot execute more /data/abc.txt because he does not have execute permission on the /data directory.

Question 48

Which command would you use to create a file named file1 in the directory named directory1 from outside the directory?

Answer 48

touch directory1/file1

Question 49

Which command would you use to create an executable file with the content 'date' in the test.sh file within /tmp?

Answer 49

echo "date" > test.sh

Question 50

Which ownership changing command can only be executed by the root user?

Answer 50

chown

Question 50

Which command would you use to run an executable file?

Answer 50

./

Question 51

Which ownership changing command can be used by the user who owns the file?

Answer 51

chgrp