use CGI 'escapeHTML';

print "\n--- take 1 ---\n";
print escapeHTML(`echo abc; echo def; echo ghi`);

print "\n--- take 2 ---\n";
print escapeHTML($b = `echo abc; echo def; echo ghi`);

print "\n--- take 3 ---\n";
$c = `echo abc; echo def; echo ghi`;
print escapeHTML($c);

##</code><code>##

--- take 1 ---
abc&#10;
--- take 2 ---
abc
def
ghi

--- take 3 ---
abc
def
ghi