From: PerlFAQ Server on
This is an excerpt from the latest version perlfaq9.pod, which
comes with the standard Perl distribution. These postings aim to
reduce the number of repeated questions as well as allow the community
to review and update the answers. The latest version of the complete
perlfaq is at http://faq.perl.org .

--------------------------------------------------------------------

9.19: How do I return the user's mail address?

On systems that support getpwuid, the $< variable, and the
"Sys::Hostname" module (which is part of the standard perl
distribution), you can probably try using something like this:

use Sys::Hostname;
$address = sprintf('%s@%s', scalar getpwuid($<), hostname);

Company policies on mail address can mean that this generates addresses
that the company's mail system will not accept, so you should ask for
users' mail addresses when this matters. Furthermore, not all systems on
which Perl runs are so forthcoming with this information as is Unix.

The "Mail::Util" module from CPAN (part of the "MailTools" package)
provides a "mailaddress()" function that tries to guess the mail address
of the user. It makes a more intelligent guess than the code above,
using information given when the module was installed, but it could
still be incorrect. Again, the best way is often just to ask the user.



--------------------------------------------------------------------

The perlfaq-workers, a group of volunteers, maintain the perlfaq. They
are not necessarily experts in every domain where Perl might show up,
so please include as much information as possible and relevant in any
corrections. The perlfaq-workers also don't have access to every
operating system or platform, so please include relevant details for
corrections to examples that do not work on particular platforms.
Working code is greatly appreciated.

If you'd like to help maintain the perlfaq, see the details in
perlfaq.pod.