EEL 358 - Operating Systems, Fall 2006

The objective of this assignment is to examine your familiarity in Unix shell scripting using the bash shell.

Create a script called uinfo that will provide information about the users of the system. By default, uinfo, invoked with no arguments, will display information about users who invoked the program, or the current user. Your script should support the following options.

-a Show information about all users of the system

-t Show the total login time for each user to be shown

-g string Show the information about members of all groups with names that contain string

-u string Show the information about users with login names that contain string

-s login|name|group Sorts the output based on the login name, full name, or group name

(requires -g, -u, or -a)

-h or -? Show program options and their descriptions

-o filename Save the output to a file called filename

-f number Show only users whose uid is greater than the indicated number

Example Default Output: (current user is ajaykr)

Login Name    :    ajaykr

Full Name     :    Ajay Kumar

User ID       :    351

Group         :    fac

Directory     :    /home/ajaykr

Shell         :    /bin/bash

Last Login    :    Fri Aug 11 07:52 (IST) on pts/1 from 10:200:5:56

------ Additional output if -t option is used ------

Total Time : 11 hours 10 minutes

Assumptions

1. Users do not login to the system for more than a day.

2. Options may be combined (e.g. uinfo -t -g ee2006 -u arun -s name).

3. The script must display error messages in the event of error (e.g. uinfo -u xyz (print an error message illustrating that there is no user name that has a substring xyz).

4. For users who have never logged in to the system, the script must display Never logged-in message.

10. Clarity, Formatting and General Layout ® Up to -5 if not followed
11. Originality ® Both copier and originator gets ZERO
12. Late Policy ® 20% reduction, allows ONLY one day delay.