PHP Find And Replace Multiple Line Using preg_replace() - Fix line break problem

php_find_and_replace_mutiple_line.php

<?php

$subject = '
    Lorem Ipsum 1
        Lorem Ipsum 1.1
    Lorem Ipsum 2
        Lorem Ipsum 2.1
            Lorem Ipsum 2.1.1
    Lorem Ipsum 3
        Lorem Ipsum 3.1
    Lorem Ipsum 4
        Lorem Ipsum 4.1
    Lorem Ipsum 5
        Lorem Ipsum 5.1
';

$find = '    Lorem Ipsum 2
        Lorem Ipsum 2.1
            Lorem Ipsum 2.1.1';
            
$replace = 'some new text ... ';

// We need replace all new line with \n
// @see https://www.npopov.com/2011/12/10/PCRE-and-newlines.html

$subject = preg_replace( "/(*BSR_ANYCRLF)\R/", PHP_EOL, $subject );
$find = preg_replace( "/(*BSR_ANYCRLF)\R/", PHP_EOL, $find );

// Convert $find to Regex Pattern
// note: 'm' means search in multi line.

$pattern = sprintf( '/(%s)/m', preg_quote( $find, '/' ) );

// Replace String

$limit = -1; // -1 means replace all, change number if you want to limit the number of replacment.

$subject = preg_replace( $pattern, $replace, $subject, $limit, $count );

echo $subject;

// @return

/*
    Lorem Ipsum 1
        Lorem Ipsum 1.1
some new text ... 
    Lorem Ipsum 3
        Lorem Ipsum 3.1
    Lorem Ipsum 4
        Lorem Ipsum 4.1
    Lorem Ipsum 5
        Lorem Ipsum 5.1
*/