Which string displayed using the ls –l command in a linux terminal indicates that group permissions are set to read and modify?

The answer is -rw-rw-r--

Explanation:

This is a permission string which refers to read and write (modify) permissions to owner and group only and read only permission for all others.

There are three types of permissions: read (r), write(w), and execute(x).

In the above string, r stands for read and w stands for write permissions. Read (r) permission allows the contents of the file to be viewed.

Write (w) permission allows modification of the contents of that file. It gives permission to edit (e.g. add and remove) files.

The first dash "-" refers to the type of file. The next rw- define the owner’s permission to the file. so the owner has permission to read and write a file only. The next rw- refers to the group permission. The members of the same group have permission to read and write a file only just as the owner. The last r-- means that all other users can only read/ view the file. In the first rw- the "-" means to remove or deny access. This means owner is granted permission read and write the file only but he cannot execute (x) the file contents. 2nd rw- means the same but for group and lastly there are two "--" after r. The first "-" denies write access and second one denies execute access.