perl -ne "/(?s)<\?php.+?[\\$]{1}/ and exit 0; exit 1" filename.txt ; echo $?

##</code><code>##

<?php  
$t60="

##</code><code>##

0000000 3c 3f 70 68 70 20 20 0d 0a 24 74 36 30 3d 22 0a
0000020

##</code><code>##

grep -Pzo "(?s)<\?php.+?[\\$]{1}([0-9a-zA-Z]+)=['\"]+" filename.txt