Display only the last error from the Laravel log file and simplify output so that it fits the single screen output. Like "tail -f storage/logs/laravel.log", but smart

TailLog.php

<?php

namespace App\Console\Commands;

use Illuminate\Console\Command;
use Illuminate\Support\Facades\Storage;

class TailLog extends Command
{
    /**
     * The name and signature of the console command.
     *
     * @var string
     */
    protected $signature = 'tail:log';

    /**
     * The console command description.
     *
     * @var string
     */
    protected $description = 'Will tail -f storage/logs/laravel.log but show only one error. This prevents heavy scrolling to find the error.';

    /**
     * Execute the console command.
     *
     * @return int
     */
    public function handle()
    {
//        system('cls');
//        echo chr(27).chr(91).'H'.chr(27).chr(91).'J';
//        $vLines = exec('tput lines'); // git bash only, gives 3000
        $vLines = exec('stty size'); // git bash only, gives 48
        list($vLines, $hCols) = trimExplode(' ', $vLines);
        $vLines -= 5;
        echo 'vLines: ', $vLines, 'x', $hCols, PHP_EOL;

        $prevLastError = -1;
        while (true) {
            $filename = Storage::path('../logs/laravel.log');
            $output = $this->tailCustom($filename, 100);
            $lines = trimExplode("\n", $output);

            $lastError = 0;
            foreach ($lines as $i => $line) {
                if (str_contains($line, 'production.ERROR')) {
                    $lastError = $i;
                    // continue to find the last error
                }
            }

            // avoid flicker when nothing changed
            if ($lastError === $prevLastError) {
                sleep(1);
                continue;
            }

            echo 'Filename: ', $filename, PHP_EOL;
            echo 'LastError: ', $lastError, PHP_EOL;
            $lines = array_slice($lines, $lastError, $vLines);

            $cwd = getcwd();
            foreach ($lines as $line) {
                $line = str_replace('\\\\', '\\', $line);
                $line = str_replace($cwd, '', $line);
                if (strlen($line) > $hCols) {
                    $line = substr($line, 0, $hCols/2-3).'...'.
                        substr($line, -$hCols/2);
                }
                echo $line, PHP_EOL;
            }
            foreach (range(count($lines), $vLines) as $i) {
                echo PHP_EOL;   // cls
            }

            $prevLastError = $lastError;
            sleep(5);
        }
    }


    /**
     * Slightly modified version of http://www.geekality.net/2011/05/28/php-tail-tackling-large-files/
     * @return string[]
     * @link http://stackoverflow.com/a/15025877/995958
     * @license http://creativecommons.org/licenses/by/3.0/
     * @author Torleif Berger, Lorenzo Stanco
     */
    function tailCustom($filepath, $lines = 1, $adaptive = true)
    {
        // Open file
        $f = @fopen($filepath, "rb");
        if ($f === false) return false;

        // Sets buffer size, according to the number of lines to retrieve.
        // This gives a performance boost when reading a few lines from the file.
        if (!$adaptive) $buffer = 4096;
        else $buffer = ($lines < 2 ? 64 : ($lines < 10 ? 512 : 4096));

        // Jump to last character
        fseek($f, -1, SEEK_END);

        // Read it and adjust line number if necessary
        // (Otherwise the result would be wrong if file doesn't end with a blank line)
        if (fread($f, 1) != "\n") $lines -= 1;

        // Start reading
        $output = '';
        $chunk = '';

        // While we would like more
        while (ftell($f) > 0 && $lines >= 0) {

            // Figure out how far back we should jump
            $seek = min(ftell($f), $buffer);

            // Do the jump (backwards, relative to where we are)
            fseek($f, -$seek, SEEK_CUR);

            // Read a chunk and prepend it to our output
            $output = ($chunk = fread($f, $seek)) . $output;

            // Jump back to where we started reading
            fseek($f, -mb_strlen($chunk, '8bit'), SEEK_CUR);

            // Decrease our line counter
            $lines -= substr_count($chunk, "\n");

        }

        // While we have too many lines
        // (Because of buffer size we might have read too many)
        while ($lines++ < 0) {

            // Find first newline and remove all text before that
            $output = substr($output, strpos($output, "\n") + 1);

        }

        // Close file and return
        fclose($f);
        return trim($output);
    }

}