chmod allows you to specify permissions for a file using octal numbers. 4000 permission is:

How do you determine the runlevel of the running system?

When you check a file's permissions, and there's an 'S' in the place of 'x' in the owner permissions section of the ls command, it means that the:

True or False: Multiple usernames on Unix are allowed to have the same UID.

To change the flog file permissions so that others besides you could neither read nor write to it, you do:

The file oldies-goldies has the details of the sale of books.The records are sorted on the names of the authors and are as follows Alexandre Dumas Alexandre Dumas Alexandre Dumas Gerald Durrell Giovanni Guareschi Giovanni Guareschi James Herriot Louisa May Alcott Louisa May Alcott Louisa May Alcott Based on the above information, what will be the output of the command uniq -u oldies-goldies ?

Which command compresses a file?

Which command will symbolically link two files in a directory?

The wc filter :

Which filter will you use to translate a set of charaters to another ?

Which option used along with the find command allows one to perform operations on the files that are located by the find command ?