## Exercise 2

 1. Write a C program that creates an empty file with permissions
    given on the command line. The name of the file comes first,
    then comes a single octal number representing the permissions.
 2. To convert the number from a string to an actual number, use
    ‹strtol› with base set to 8 and ‹endptr› set to NULL. See also
    ‹man strtol›.
 3. You will want to call the C function ‹umask›, which works the
    same as the shell builtin we have seen before.

This is pretty much all about permissions / access modes. Let's have
a look at users using shell commands for a bit -- we will look at C
APIs later on. Next stop: ‹users.sh›.
