010-160 - LPI Linux Essentials File Permissions and Ownership Questions and Answers

Question 1

A system administrator needs to set the permissions for a shell script named `deploy.sh`. The requirements are that the owner can read, write, and execute it; members of the group can read and execute it; and all other users can only read it. Which of the following `chmod` commands will set these permissions correctly using octal notation?

Accepted Answer

chmod 754 deploy.sh

Answer

In octal notation, read is 4, write is 2, and execute is 1. The permissions are calculated for owner, group, and other. Owner (read+write+execute) = 4+2+1=7. Group (read+execute) = 4+1=5. Other (read) = 4. Therefore, the correct octal code is 754.

Question 2

Which command is used to change the ownership of `file.txt` to the user `anne` and the group `developers` in a single operation?

Accepted Answer

chown anne:developers file.txt

Answer

The `chown` command is used to change file ownership. The syntax `chown user:group filename` allows changing both the user owner and the group owner simultaneously.

Question 3

A user runs the `umask 0027` command. What will the default permissions be for a newly created directory afterwards?

Accepted Answer

drwxr-x---

Answer

The system starts with default permissions for a directory, which is 777 (`rwxrwxrwx`). The `umask` value is subtracted from this default. 777 - 027 results in 750. This octal value corresponds to `rwxr-x---`.

Question 4

What is the primary function of the execute (`x`) permission when it is set on a directory?

Accepted Answer

It allows a user to enter the directory with the `cd` command.

Answer

For a directory, the execute (`x`) permission grants the ability to traverse it or enter it, for example, by using the `cd` command. Listing contents requires read (`r`) permission, and modifying the directory's contents (creating/deleting files) requires write (`w`) permission.

Question 5

A file has the permissions `-rw-r--r--`. The owner wants to add write permission for the group members without affecting any other permissions. Which of the following commands will achieve this?

Accepted Answer

chmod g+w file.txt

Answer

The symbolic notation `g+w` specifically targets the 'group' (`g`) and 'adds' (`+`) the 'write' (`w`) permission. Using octal `664` would work in this specific case, but it resets all permissions rather than just adding one. The `g+w` syntax is the most precise way to add a permission without altering others.

(010-160) LPI Linux Essentials Practice Test

(010-160) LPI Linux Essentials Practice Test

010-160 - LPI Linux Essentials File Permissions and Ownership Questions and Answers