<?php
$var_name = 'FIRM_ID';
$re = '/' . $var_name . '\s*=\s*\K[^;]*/';
$str = 'FIRM_ID = MC0356400000; TAG = EQTV; CURR_CODE = SUR; CLIENT_CODE = FR334; LIMIT_KIND = 1; OPEN_BALANCE = 4822.84; OPEN_LIMIT = 0.00; LEVERAGE = 0;';
echo "\n" . $m[0];
PD9waHAKCiR2YXJfbmFtZSA9ICdGSVJNX0lEJzsKJHJlID0gJy8nIC4gJHZhcl9uYW1lIC4gJ1xzKj1ccypcS1teO10qLyc7CiRzdHIgPSAnRklSTV9JRCA9IE1DMDM1NjQwMDAwMDsgVEFHID0gRVFUVjsgQ1VSUl9DT0RFID0gU1VSOyBDTElFTlRfQ09ERSA9IEZSMzM0OyBMSU1JVF9LSU5EID0gMTsgT1BFTl9CQUxBTkNFID0gNDgyMi44NDsgT1BFTl9MSU1JVCA9IDAuMDA7IExFVkVSQUdFID0gMDsnOwpwcmVnX21hdGNoKCRyZSwgJHN0ciwgJG0pOwpwcmludF9yKCRtKTsKZWNobyAiXG4iIC4gJG1bMF07