How can the combination of functions like `str_replace`, `nl2br`, and `preg_replace` be effectively used to manipulate text content in PHP?

To manipulate text content in PHP, you can use a combination of functions like `str_replace`, `nl2br`, and `preg_replace`. `str_replace` can be used to replace specific strings within a text, `nl2br` can convert newlines to HTML line breaks, and `preg_replace` can perform more complex pattern-based replacements. By chaining these functions together, you can effectively manipulate text content in PHP.

$text = "Hello, this is a sample text.\nIt has multiple lines that need to be replaced.";
$text = str_replace('sample', 'modified', $text); // Replace 'sample' with 'modified'
$text = nl2br($text); // Convert newlines to HTML line breaks
$text = preg_replace('/[aeiou]/', '*', $text); // Replace vowels with '*'
echo $text;