- sprintf: documentation ( source)
<?php
$str1 = 'Hello';
$str2 = 'Hello world!';
echo sprintf("[%s]",$str1)."\n"; // String
echo sprintf("[%8s]",$str1)."\n"; // Right-justifies the string with spaces
echo sprintf("[%-8s]",$str1)."\n"; // Left-justifies the string with spaces
echo sprintf("[%08s]",$str1)."\n"; // Zero-padding
echo sprintf("[%'*8s]",$str1)."\n"; // Adds "*"
echo sprintf("[%8.8s]",$str2)."\n"; // Left-justifies the string with spaces (cuts off characters after the specified value)