Homework 2:  Due after the midterm.  5 points.

NOTICE:  Please read this entire file before starting.  There is
         an offensive "Collaboration Policy" notice at the end
         that, though it shouldn't be necessary to say, you should
         be aware of.

Here are two scripts, adduser and isadir:

http://www.classes.cs.uchicago.edu/classes/current/CS501/homework/adduser
http://www.classes.cs.uchicago.edu/classes/current/CS501/homework/isadir

adduser prompts the operator for account information (login name,
etc), giving a default value for each.  The user can set the value
(by supplying something) or accept the default by just hitting
return.

isadir is an example of a script that parses standard UNIX-style
flags on the command line.  Please read it.

Augment the adduser script with non-interactive functionality.
Use getopts (use isadir as an example) to parse the command
line.

The new adduser should accept the following arguments:

  -l login
  -c crypt
  -u uid
  -g gid
  -n name (gecos)
  -h home directory
  -s shell

If any of the above arguments aren't supplied, the user should
be prompted (using a default value, as the original adduser does)
for a value.

In addition, adduser should accept the flag:

  -f

If the user supplies a "-f" (it stands for "force") flag to the
script, the script should just use the default values and not
prompt the user.

If the script ever has to prompt the user, it should also ask them
before adding the line to the password file.  But if all of the
arguments are supplied, or if the force flag is given, it should
not ask the user before adding the line.

Setup:

  Before testing the scripts, you should setup a password file
  and group file for use.  Take the example ones I put in the
  homework directory:

http://www.classes.cs.uchicago.edu/classes/current/CS501/homework/passwd
http://www.classes.cs.uchicago.edu/classes/current/CS501/homework/group

Collaboration Policy:

  Any homeworks that "look too similar" to another persons homework
  will be subject to intense scrutiny.  You will be obligated to
  come in to my office and do another (similar) assignment in front
  of me.  You are free to discuss how to do the assignment with other
  students, but your implementation must be your own.