laravel installation error in ubuntu 16.04 - php

Question

I am having trouble while installation error in laravel.
First install xampp in ubuntu 16.04.
After that
cd /opt/lampp/htdocs/
composer create-project --prefer-dist laravel/laravel blog
installation laravel with composer some error occurs
E: Package 'php5-mcrypt' has no installation candidate
shwekayin#shwekayin-VirtualBox:/opt/lampp/htdocs$ composer create-project --prefer-dist laravel/laravel blog1
Installing laravel/laravel (v5.3.0)
- Installing laravel/laravel (v5.3.0)
Loading from cache
Created project in blog1
> php -r "file_exists('.env') || copy('.env.example', '.env');"
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 v5.3.4 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
- laravel/framework v5.3.3 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
- laravel/framework v5.3.2 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
- laravel/framework v5.3.1 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
- laravel/framework v5.3.0 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
- Installation request for laravel/framework 5.3.* -> satisfiable by laravel/framework[v5.3.0, v5.3.1, v5.3.2, v5.3.3, v5.3.4].
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-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-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.
How can I fix this error. My xampp php version is 7.0.10

Answer 1

The error message details what is wrong:
laravel/framework v5.3.4 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
Run sudo apt install php-mbstring to install it.

Answer 2

Run this
sudo apt-get install php libapache2-mod-php php-mcrypt php-mysql
if you no need to update php 7 again, Just run this
sudo apt-get install php-mcrypt
Install optional components these as well
libnet-libidn-perl - Perl bindings for GNU Libidn
php-all-dev - package depending on all supported PHP development packages
php-cgi - server-side, HTML-embedded scripting language (CGI binary) (default)
php-cli - command-line interpreter for the PHP scripting language (default)
php-common - Common files for PHP packages
php-curl - CURL module for PHP [default]
php-dev - Files for PHP module development (default)
php-gd - GD module for PHP [default]
php-gmp - GMP module for PHP [default]
sudo apt-get install package_name
Best ever tutorial How To Install Linux, Apache, MySQL, PHP (LAMP) stack on Ubuntu 16.04 -used and works for me

Answer 3

By default Ubuntu 16.04 has php7.0 installed. You need to install first php5 (in your case here). And then switch to php5 before reinstalling laravel.
https://askubuntu.com/questions/756879/cant-install-php5-on-ubuntu-16-04