package MySystem;

use Exporter 'import';
@EXPORT = qw(system);

sub system {
    print "wrapped system(): @_\n";
}
1;

##</code><code>##

#!/usr/bin/perl

use MySystem;

system "echo foo";

package SomeOtherModule;

system "echo bar";

##</code><code>##

$ ./test.pl
wrapped system(): echo foo
bar