How to resolve unexpected token error with grep, regex, and PHP? - php

Question

I know REGEX well enough but am stuck on this one. I am using PHP 5.4 to shell_exec() a grep statement with REGEX inside it to capture the SKU in a text file. In php I don't see an error but the grep doesn't work.
The goal is to capture the SKU in this text:
{'Product_Product_SKU': 'DOP36M94DPM'},
PHP Code:
$cmdSKU1 = 'grep -Po \'(?<=\{\'Product_Product_SKU\':\s{15}\').+?(?=\'\}\,)\' '.$FileName;
$chkSKU1 = trim(shell_exec($cmdSKU1));
Furthermore, when I look at the $cmdSKU1 variable in the debugger tool of the IDE I am using it's value is this as one line:
grep -Po '(?<=\{'Product_Product_SKU':\s{15}').+?(?='\}\,)' /opt/web/default/RetailerParsing/RetailerDownload/MDD30TMSTH__20220113091043.htm
Furthermore some more, when I paste it into the Ubuntu console it gives me the error:
-bash: syntax eror near unexpected token `)'
Even if I go back and escape the exposed single quotes. Infact, I escaped everything [^A-Za-z0-9] just to make sure! No beans.
Lastly, if I try to double escape the single quotes within the REGEX in the PHP IDE I get a red squiggly underline error under the words Produce_Product_SKU.

Answer 1

You're not escaping the shell command correctly. Instead of doing it manually, you should use ​escapeshellarg:
$cmdSKU1 = join(" ", array_map( 'escapeshellarg', array(
​"grep",
​"-Po",
​"(?<={'Product_Product_SKU':\s{15}').+?(?='},)",
​$FileName
)));
$chkSKU1 = trim(shell_exec($cmdSKU1));
That said, why not directly use preg_match and save a call to a non POSIX external command?
$string = "{'Product_Product_SKU': 'DOP36M94DPM'},";
preg_match("/{'Product_Product_SKU':\s{15}'([^']+)'}/", $string, $matches);
var_dump($matches[1]);
string(11) "DOP36M94DPM"
Of course you'll have to read the file inside php, but it may be worth the extra code.

Answer 2

You don't need regex at all here, and certainly not a shell_exec. Just split on ' and take the 4th (0-indexed) value out of the resulting array:
$str = "{'Product_Product_SKU': 'DOP36M94DPM'},";
$sku = explode("'", $str)[3];
var_dump($sku);
Yields:
string(11) "DOP36M94DPM"
Also note PHP 5.4 was end-of-lifed over 6 years ago. You really should update.