Caveats
This package is included as a show case, illustrating a few Perl
features. It shouldn't be used for production programs. Although it
does provide a simple interface for obtaining the standard output of
arbitrary commands, there may be better ways of achieving what you
need.

Running shell commands while obtaining standard output can be done with
the C<qx/STRING/> operator, or by calling C<open> with a filename
expression that ends with C<|>, giving you the option to process one
line at a time. If you don't need to process standard output at all,
you might use C<system> (in preference of doing a print with the
collected standard output).

Since Shell.pm and all of the aforementioned techniques use your
system's shell to call some local command, none of them is portable
across different systems. Note, however, that there are several built
in functions and library packages providing portable implementations of
functions operating on files, such as: C<glob>, C<link> and C<unlink>,
C<mkdir> and C<rmdir>, C<rename>, C<File::Compare>, C<File::Copy>,
C<File::Find> etc.