## Exercise 1

 1. Write a shell script that does the following:
    a. takes one argument, an IP address (see also below)
    b. resolves the address to a hostname
    c. resolves the hostname back to an (IPv4) address
    d. prints ‘yes’ if they match
    e. prints ‘no’ if they are mismatched
    f. prints ‘error’ if an error happens
    
 2. You can run the script as ‹sh chkrdns.sh 4.2.2.2›.
 3. The address will be available in the variable ‹$1›.
 4. Anything other than ‘yes’, ‘no’ and ‘error’ should go to
    ‹stderr› (but you can print what you like there).
 5. To redirect the ‹stdout› to ‹stderr› for a command, you can use
    ‹1>&2› after the command, like so: echo hello 1>&2
 6. Hints: this should be quite doable with just ‹cut› and
    ‹$(command)›.

Let's continue to ‹dig.sh›.
