Why doesn't laravel want to run localhost localhost:8000?

Question

ubuntu

Installed laravel framework on Ubuntu 16.04 OS. I decided to start the local host with the command php artisan serve
So laravel gives such an error

PHP Warning:  require(/var/www/laravel/bootstrap/../vendor/autoload.php): failed to open stream: No such file or directory in /var/www/laravel/bootstrap/autoload.php on line 17
PHP Fatal error:  require(): Failed opening required '/var/www/laravel/bootstrap/../vendor/autoload.php' (include_path='.:/usr/share/php') in /var/www/laravel/bootstrap/autoload.php on line 17

I read what I need to install composer with the command I composer install
installed it, and after installation I got this

Cannot create cache directory /home/heartprogrammer/.composer/cache/repo/https---packagist.org/, or directory is not writable. Proceeding without cache
Cannot create cache directory /home/heartprogrammer/.composer/cache/files/, or directory is not writable. Proceeding without cache
Loading composer repositories with package information
Updating dependencies (including require-dev)
Your requirements could not be resolved to an installable set of packages.

  Problem 1
    - laravel/framework v5.2.9 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.2.8 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.2.7 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.2.6 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.2.5 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.2.4 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.2.39 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.2.38 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.2.37 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.2.36 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.2.35 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.2.34 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.2.33 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.2.32 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.2.31 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.2.30 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.2.3 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.2.29 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.2.28 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.2.27 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.2.26 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.2.25 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.2.24 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.2.23 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.2.22 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.2.21 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.2.20 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.2.2 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.2.19 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.2.18 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.2.17 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.2.16 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.2.15 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.2.14 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.2.13 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.2.12 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.2.11 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.2.10 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.2.1 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.2.0 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - Installation request for laravel/framework 5.2.* -> satisfiable by laravel/framework[v5.2.0, v5.2.1, v5.2.10, v5.2.11, v5.2.12, v5.2.13, v5.2.14, v5.2.15, v5.2.16, v5.2.17, v5.2.18, v5.2.19, v5.2.2, v5.2.20, v5.2.21, v5.2.22, v5.2.23, v5.2.24, v5.2.25, v5.2.26, v5.2.27, v5.2.28, v5.2.29, v5.2.3, v5.2.30, v5.2.31, v5.2.32, v5.2.33, v5.2.34, v5.2.35, v5.2.36, v5.2.37, v5.2.38, v5.2.39, v5.2.4, v5.2.5, v5.2.6, v5.2.7, v5.2.8, v5.2.9].

  To enable extensions, verify that they are enabled in those .ini files:
    - /etc/php/5.6/cli/php.ini
    - /etc/php/5.6/cli/conf.d/10-opcache.ini
    - /etc/php/5.6/cli/conf.d/10-pdo.ini
    - /etc/php/5.6/cli/conf.d/15-xml.ini
    - /etc/php/5.6/cli/conf.d/20-calendar.ini
    - /etc/php/5.6/cli/conf.d/20-ctype.ini
    - /etc/php/5.6/cli/conf.d/20-dom.ini
    - /etc/php/5.6/cli/conf.d/20-exif.ini
    - /etc/php/5.6/cli/conf.d/20-fileinfo.ini
    - /etc/php/5.6/cli/conf.d/20-ftp.ini
    - /etc/php/5.6/cli/conf.d/20-gettext.ini
    - /etc/php/5.6/cli/conf.d/20-iconv.ini
    - /etc/php/5.6/cli/conf.d/20-json.ini
    - /etc/php/5.6/cli/conf.d/20-pdo_sqlite.ini
    - /etc/php/5.6/cli/conf.d/20-phar.ini
    - /etc/php/5.6/cli/conf.d/20-posix.ini
    - /etc/php/5.6/cli/conf.d/20-readline.ini
    - /etc/php/5.6/cli/conf.d/20-shmop.ini
    - /etc/php/5.6/cli/conf.d/20-simplexml.ini
    - /etc/php/5.6/cli/conf.d/20-sockets.ini
    - /etc/php/5.6/cli/conf.d/20-sqlite3.ini
    - /etc/php/5.6/cli/conf.d/20-sysvmsg.ini
    - /etc/php/5.6/cli/conf.d/20-sysvsem.ini
    - /etc/php/5.6/cli/conf.d/20-sysvshm.ini
    - /etc/php/5.6/cli/conf.d/20-tokenizer.ini
    - /etc/php/5.6/cli/conf.d/20-wddx.ini
    - /etc/php/5.6/cli/conf.d/20-xmlreader.ini
    - /etc/php/5.6/cli/conf.d/20-xmlwriter.ini
    - /etc/php/5.6/cli/conf.d/20-xsl.ini
  You can also run `php --ini` inside terminal to see which files are used by PHP in CLI mode.

It also fails to run on localhost. What is it connected with?

Answer 1

you are missing extensions.
apt-get install php5-*name modules

Answer 2

sudo apt-get install php7.0-mbstring

Answer 3

directory is not writable

This suggests that you need to deal with folder permissions
Try
sudo chmod -R 777 /home/heartprogrammer/.composer/

Answer 4

In the php.ini file, you need to find the line
;extension=mbstring
and uncomment it (remove the ";" before)

Answer 5

Try learning docker and how to run laravel in docker. It has never been so easy before. the truth will have to be downcast at the beginning
https://maxyc.ru/programming/laravel/laravel-docker/
wrote point by point what where where