- substr: documentation ( source)
- strpos: documentation ( source)
<?php
$mystring = '05/07/2017 06:14:22: #1 atualizacao de status da entrega UN085464466BR para a nova situacao 0 em 2017-07-05 06:14:22 [imagens/33/2017/06/30/UN085464466BR.jpg][Sucesso]';
$pos1 = strpos($mystring, 'nova situacao ');
$pos2 = strpos($mystring, ' em');
echo '='.substr($mystring, $pos1+14, $pos2-($pos1+14)).'=';