prince_admin@testingwithdb:~/magento2$ php bin/magento setup:upgrade
PHP Warning: PHP Startup: Unable to load dynamic library 'gd2' (tried: /usr/lib/php/20170718/gd2 (/usr/lib/php/20170718/gd2: cannot open shared object file: No such file or directory), /usr/lib/php/20170718/gd2.so (/usr/lib/php/20170718/gd2.so: cannot open shared object file: No such file or directory)) in Unknown on line 0
PHP Warning: Module 'fileinfo' already loaded in Unknown on line 0 Deprecated Functionality: The each() function is deprecated. This message will be suppressed on further calls in /var/www/html/prince/magento2/vendor/colinmollenhour/cache-backend-file/File.php on line 81
As above, i can not use bin/magento to add my new created module.. Can anyone kindly help me?
This isn't a problem with Magento but with PHP. You're missing the gd2 library.
try the following (borrowed from here):
sudo apt-get install php5-gd