$re = '/https:\/\/s3.amazonaws.com\/(.?[^\/]*)\/(.*)/m';
$str = 'https://s3.amazonaws.com/jge-catalog-lake/guanaTest/Pet_Resource_Template.gdb.zip
https://s3.amazonaws.com/jge-data-platform-primary-automation-prod/DKU_TSHIRTS/orders_copy/out-s0.csv.gz
https://s3.amazonaws.com/jge-data-platform-primary-automation-prod/Approved_Data/Pet_Sed_Thick/Pet_Sediment_Thickness_Through_Time_P2V2_Resampled.tif.zip
';
$subst = "[\1] | [\2]";
$result = preg_replace($re, $subst, $str);
echo "The result of the substitution is ".$result;
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php