The IO::Capture Module defines an abstract base class that can be
used to create any number of useful sub-classes that capture
output being sent on a filehandle such as STDOUT or STDERR.

Several modules come with the distribution that define subclasses
of IO::Capture to do just that. (I.e., capture STDOUT and STDERR)
See the man page IO::Capture::Overview for a discussion of these
modules and how to build a module to sub-class the B<IO::Capture>
class yourself.