Sreenivas Mekala you are missing extensions. That is a Operations system issue.

mbstring and xml are missing but you have be sure if you read the message it says php-7.1 not 7.2 :) you have to install the correct one

apt-cache search php | grep xml

to list the xml extension :)

You'r right bro. when i run sudo apt-get install php7.1-xml. It produces following error. Reading package lists... Done Building dependency tree
Reading state information... Done E: Unable to locate package php7.1-xml E: Couldn't find any package by glob 'php7.1-xml' E: Couldn't find any package by regex 'php7.1-xml'

After that i run sudo apt-get install php7.2-xml. Problems are solved. composer install command works. But main issue is here . i got parse error. Parse error: syntax error, unexpected '=' in /opt/lampp/htdocs/myapp/vendor/laravel/framework/src/Illuminate/Support/Arr.php on line 388

it leads to php version mismatching. But when i run php artisan serv it works fine. I think problem is in Apache2

Sreenivas Mekala

maybe try to start the php dev server instead of the lamp stack

go in the public folder of you app and type

php -S localhost:8000

php.net/manual/en/features.commandline.webserver.…

so you don't need the whole LAMPP but the php is running directly with the developer server.

maybe this helps?