Write a program that reads in a machine hostname and a
username, builds the command:
/usr/bin/ssh <machine> /usr/bin/finger <user>
in a string and uses the system(3) function on that string to output
the information retrieved remotely. Note that you have to validate your
input and handle it securely. For the characteristics of a hostname, look
up \Hostname" on Wikipedia. As far as \user" is concerned, it has to
be a string of alphabetic strings, where, if there are digits at the end,
it may not start with a capital letter. Choose a reasonable maximum
length for the username, taking into account that it may be a real name
(like Sklodovskaya or even longer?).