Answer to Question #162818 in UNIX/Linux Programming for khnnn

Question

Assume that you are working as system administrator and managing the Access modes of software System, Explain the File Permissions with respect to users by executing commands and show the output. (Select and name any Software Application of your choice).

Answer 1

String with file permissions looks on the UNIX systems looks like the following:  drwxr-xrw- 

It can be altered via the chmod command.

The symbols can be interpreted as:

"-" - not set 

d - directory

r - read

w - write

x - execute

The string is actually split into 4 distinct sections: 

1  2   3   4

d|rwx|r-x|rw- 

1 - Marks whether the file is a directory or not.

2 - Owner permissions. The owner's permissions determine what actions the owner of the file can perform on the file.

3 - Group permissions. The group's permissions determine what actions a user, who is a member of the group that a file belongs to, can perform on the file.

4 - Other (world) permissions − The permissions for others indicate what action all other users can perform on the file.

Imagine that there is an executable program hello and we are its owner. Then the permissions drw-r-xrw- would allow us to write and read it but executing it via "./hello" will yield the message:

The file './hello' is not executable by this user 

Reference: https://www.tutorialspoint.com/unix/unix-file-permission.htm