Exercises

1. Try to install the XML::RSS Perl module. As you will see in the bonus chapter, we use this module in our sysadmin application to parse an RSS data stream that contains the latest security headlines.

2. Change the hello.pl program to display your own hometown.

3. Implement an application that is similar to list_users.pl to display the system groups: the gid followed by the group name . Hint: The group information is stored in /etc/group .

4. Write a small snippet of code to invoke the lsmod command and display its output. The lsmod application shows information about all loaded kernel modules. Hint: Try to use either backticks or a piped open to communicate with the external application, as you will reuse this code in the next question.

5. Extend the snippet of code you wrote for the previous question to display only the kernel module name and its size . There are many ways to accomplish this task, but using a regular expression will garner you bonus points.

6. Change the Disk Usage Monitor application to send the system administrator, or [e-mail] , a copy of the warning message. Hint: Use the perldoc command to learn more about the Mail::Send module and its functionality.