Regular File Ownerships and Permissions

Question 1

Files have a…?

Answer 1

user owner, group owner, and a set of permissions.

Question 2

Three permission types…?

Answer 2

(r)ead, (w)rite, and e(x)ecute.

Question 3

Three access classes…?

Answer 3

(u)ser owner, (g)roup owner, and (o)ther.

Question 4

Viewing ownerships and permissions…?

Answer 4

ls -l

Question 5

Modifying ownerships and permissions…?

Answer 5

chmod, chgrp, and chown.

Question 6

Linux is a multiuser environment, so many different people are often…?

Answer 6

working with a single set of files and directories a the same time. (Some of these files are intended to be shared, so that many people can view and edit the file. For example, someone might be listing suggested gifts they would like to receive for an upcoming birthday. The more people who are able to read the file, the better. Other files, the user might want to keep private. Few people would want anyone else to be able to read their diary. Someone might want a file to be readable to everyone on the system, and allow a few select users on the system to modify the file as well.)

Question 7

Every file in Linux has three properties that allows users to control…?

Answer 7

who can access the file and how: a user owner, a group owner, and a set of allowed permissions.

Question 8

When a user creates a file, that user becomes the…?

Answer 8

file’s user owner, and (usually) the primary group of the user becomes the file’s group owner.

Question 9

A user cannot change the user owner of a file, but a user has some abilities to change the group owner. The permission bits define how…?

Answer 9

three different classes of users can user the file: the file’s owner, members of the group that owns the file, and everyone else.

Question 10

When deciding who can access a file, a user can distinguish between…?

Answer 10

three types of permissions.

Question 11

Someone can view a file if they have …?

Answer 11

read permissions.

Question 12

Some can modify a file if they have…?

Answer 12

write permissions.

Question 13

Someone can use the file as a command if they have…?

Answer 13

execute permissions.

Question 14

In order to start up an application or run a script, the file containing the application or script must be…?

Answer 14

Executable. (Normal (data) files do not use the executable permission type)

Question 15

Each file has a set of read, write, and execute permissions for three different classes of file access. The first set is used for…?
The second set is used for…?
And the last set is used for…?

Answer 15

First set = owner of a file
Second set = members of the group that owns the file.
Third set = Used for everyone who doesn’t fit into the first two groups.

Question 16

A file’s permissions are usually show using a series of…?

Answer 16

nine character, such as rwxr-xr-x. The first three letters represent the “user” permissions, the next three the “group” permissions, and the last three the “other” permission. A letter indicates that the corresponding permission is enabled, while a disabled permission is represented by dash.

Question 17

When someone tries to access a file, Linux asks these questions in order…?

Answer 17

1. Does the user own the file? if so, the user permissions are used.
2. is the user a member of the group that owns the file? if so, the group permissions are used.
3. Otherwise, the other permissions are used.