无法在 Ubuntu 18.10 LEMP 堆栈上安装 Laravel？

Question

运行laravel new 时，我收到所有这些错误。我理解他们的意思，但我很好奇为什么会发生这种情况，在 Windows 上一切正常。

我安装了php，Ubuntu怎么会报错？它是否从 php 安装中排除了很多东西？我不太确定为什么它会引起如此大的戏剧性，这是我今天经历的第 10 组错误，我担心我做错了什么。

我的 LEMP 堆栈遵循了这个：https://www.digitalocean.com/community/tutorials/how-to-install-linux-nginx-mysql-php-lemp-stack-ubuntu-18-04

另外，在我什至可以使用laravel 命令之前，我每次打开终端时都必须运行export PATH="~/.composer/vendor/bin:$PATH"。有没有办法解决这个问题？

  Problem 1
    - Installation request for erusev/parsedown v1.7.2 -> satisfiable by erusev/parsedown[v1.7.2].
    - erusev/parsedown v1.7.2 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
  Problem 2
    - Installation request for laravel/framework v5.8.7 -> satisfiable by laravel/framework[v5.8.7].
    - laravel/framework v5.8.7 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
  Problem 3
    - Installation request for phar-io/manifest 1.0.3 -> satisfiable by phar-io/manifest[1.0.3].
    - phar-io/manifest 1.0.3 requires ext-dom * -> the requested PHP extension dom is missing from your system.
  Problem 4
    - Installation request for phpunit/php-code-coverage 6.1.4 -> satisfiable by phpunit/php-code-coverage[6.1.4].
    - phpunit/php-code-coverage 6.1.4 requires ext-dom * -> the requested PHP extension dom is missing from your system.
  Problem 5
    - Installation request for phpunit/phpunit 7.5.7 -> satisfiable by phpunit/phpunit[7.5.7].
    - phpunit/phpunit 7.5.7 requires ext-dom * -> the requested PHP extension dom is missing from your system.
  Problem 6
    - Installation request for theseer/tokenizer 1.1.0 -> satisfiable by theseer/tokenizer[1.1.0].
    - theseer/tokenizer 1.1.0 requires ext-dom * -> the requested PHP extension dom is missing from your system.
  Problem 7
    - laravel/framework v5.8.7 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - beyondcode/laravel-dump-server 1.2.2 requires illuminate/console 5.6.*|5.7.*|5.8.* -> satisfiable by laravel/framework[v5.8.7].
    - Installation request for beyondcode/laravel-dump-server 1.2.2 -> satisfiable by beyondcode/laravel-dump-server[1.2.2].

  To enable extensions, verify that they are enabled in your .ini files:
    - /etc/php/7.2/cli/php.ini
    - /etc/php/7.2/cli/conf.d/10-mysqlnd.ini
    - /etc/php/7.2/cli/conf.d/10-opcache.ini
    - /etc/php/7.2/cli/conf.d/10-pdo.ini
    - /etc/php/7.2/cli/conf.d/20-calendar.ini
    - /etc/php/7.2/cli/conf.d/20-ctype.ini
    - /etc/php/7.2/cli/conf.d/20-exif.ini
    - /etc/php/7.2/cli/conf.d/20-fileinfo.ini
    - /etc/php/7.2/cli/conf.d/20-ftp.ini
    - /etc/php/7.2/cli/conf.d/20-gettext.ini
    - /etc/php/7.2/cli/conf.d/20-iconv.ini
    - /etc/php/7.2/cli/conf.d/20-json.ini
    - /etc/php/7.2/cli/conf.d/20-mbstring.ini
    - /etc/php/7.2/cli/conf.d/20-mysqli.ini
    - /etc/php/7.2/cli/conf.d/20-pdo_mysql.ini
    - /etc/php/7.2/cli/conf.d/20-phar.ini
    - /etc/php/7.2/cli/conf.d/20-posix.ini
    - /etc/php/7.2/cli/conf.d/20-readline.ini
    - /etc/php/7.2/cli/conf.d/20-shmop.ini
    - /etc/php/7.2/cli/conf.d/20-sockets.ini
    - /etc/php/7.2/cli/conf.d/20-sysvmsg.ini
    - /etc/php/7.2/cli/conf.d/20-sysvsem.ini
    - /etc/php/7.2/cli/conf.d/20-sysvshm.ini
    - /etc/php/7.2/cli/conf.d/20-tokenizer.ini
    - /etc/php/7.2/cli/conf.d/20-zip.ini
  You can also run `php --ini` inside terminal to see which files are used by PHP in CLI mode.

Answer 1

您使用的是哪个 PHP 版本？

您需要安装 mbstring 扩展。

假设它是 PHP7.2，你可以安装 Laravel 所需的依赖，如：

sudo apt install php7.2-mbstring php7.2-dom php7.2-pdo php7.2-xml php7.2-common php7.2-bcmath php7.2-json php7.2-cli php7.2-fpm php7.2-mysql

编辑：该 LEMP 指南不包括 php 扩展的安装。

假设它是 Laravel 5.8，根据docs，你还需要安装一些扩展。相应地更新我的答案

注意：如果您需要 MySQL 等（因为您提到了 LEMP），我还添加了 php7.2-mysql。

虽然，就像我在 cmets 中提到的那样，我更喜欢 Ondrej Sury 的 PPA 并安装 PHP7.3 及其扩展。