perl -i -pe'
  BEGIN { $/ = "}\n" }
  s/@{[ <<REGEX ]}/@{[ <<STRING ]}/g;
if ((!(\$session_login)) or (\$session_access < 5)) { 
header("Window-Target: _top"); 
header("Location: index.php"); 
}
REGEX
if ((!(\$session_login)) or (\$session_access < 5)) { 
header("Window-Target: _top"); 
header("Location: index.php"); 
exit;
}
STRING
' *.php