我正在尝试安装laravel并应用命令
composer create-project --prefer-dist laravel / laravel blog
我收到以下错误......它可能是什么？
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 v5.2.43 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. - laravel/framework v5.2.42 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. - laravel/framework v5.2.40 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. - laravel/framework 5.2.41 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. - Installation request for laravel/framework 5.2.* -> satisfiable by laravel/framework[5.2.41, 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，v5.2.40，v5.2.42，v5.2.43，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/7.0/cli/php.ini - /etc/php/7.0/cli/conf.d/10-mysqlnd.ini - /etc/php/7.0/cli/conf.d/10-opcache.ini - /etc/php/7.0/cli/conf.d/10-pdo.ini - /etc/php/7.0/cli/conf.d/20-calendar.ini - /etc/php/7.0/cli/conf.d/20-ctype.ini - /etc/php/7.0/cli/conf.d/20-exif.ini - /etc/php/7.0/cli/conf.d/20-fileinfo.ini - /etc/php/7.0/cli/conf.d/20-ftp.ini - /etc/php/7.0/cli/conf.d/20-gettext.ini - /etc/php/7.0/cli/conf.d/20-iconv.ini - /etc/php/7.0/cli/conf.d/20-json.ini - /etc/php/7.0/cli/conf.d/20-mcrypt.ini - /etc/php/7.0/cli/conf.d/20-mysqli.ini - /etc/php/7.0/cli/conf.d/20-pdo_mysql.ini - /etc/php/7.0/cli/conf.d/20-phar.ini - /etc/php/7.0/cli/conf.d/20-posix.ini - /etc/php/7.0/cli/conf.d/20-readline.ini - /etc/php/7.0/cli/conf.d/20-shmop.ini - /etc/php/7.0/cli/conf.d/20-sockets.ini - /etc/php/7.0/cli/conf.d/20-sysvmsg.ini - /etc/php/7.0/cli/conf.d/20-sysvsem.ini - /etc/php/7.0/cli/conf.d/20-sysvshm.ini - /etc/php/7.0/cli/conf.d/20-tokenizer.ini You can also run `php --ini` inside terminal to see which files are used by PHP in CLI mode.