BEGIN { require Foo; Foo->import(@LIST) }

##</code><code>##

while (<>) {
     # ... your code here ...
     print $_;
}

##</code><code>##

perl -p -e "$_ = reverse $_" f1

##</code><code>##

print -p -e "$_ = reverse $_; $i ++; END { print qq'Total lines $i.' }" f1

##</code><code>##

$a = 6;
*b = \ $a;
$b = 5;
print $a;  # prints 5

@a = (1, 2, 3);
*b = \ @a;
pop @b;
print "@a"; # prints 1 2

##</code><code>##

use Shell;

$a = Shell::cat("file.text");
Shell::cp("a.txt", "b.txt");

##</code><code>##

package Shell;

sub cat {
     `cat @_`
}

sub cp {
     `cp @_`
}

##</code><code>##

package Shell;

sub AUTOLOAD {
     $AUTOLOAD =~ s/^.*:://; # Strip out the package name from the sub's name (in this case Shell::)
     `$AUTOLOAD @_`
}