firewall-cmd --zone=public --add-port=3333/tcp
firewall-cmd --zone=public --add-port=27017/tcp
firewall-cmd --zone=public --list-all
mongoexport --db ppt --collection users --out users.json
mongoexport --db ppt --collection companies --out companies.json
mongoexport --db ppt --collection summer-practice-programs --out summer-practice-programs.json