In Soviet Russia, they used to shoot people for writing code like that:

print '<h3>Testing Use Commands:'.encode_entities($uselist)."</h3>\n";
+ 
print '<pre>'."\n"; 
for my $use (split(' ',$uselist)) { addin($use); } 
print '</pre>'."\n"; 
print '<form method="POST">'."\n"; 
print '<table><tr>'."\n";
print '<td style="vertical-align:top;">Modules to test<br>CASE MATTERS
+!<br>Just like in perl</td>'."\n";
print '<td style="vertical-align:top;"> </td>'."\n";
print '<td style="vertical-align:top;"><textarea  rows="10" cols="50" 
+name="uselist">'.$uselist0.'</textarea></td>'."\n"; 
print '</tr><tr>'."\n"; 
print '<td style="vertical-align:top;"><input type="submit" value="Tes
+tIt"></td>'."\n"; 
print '</tr></table> </form>'."\n"; 
print '</body></html>';
[download]

Use a templating solution. At least just use one print and provide the strings as a list.