ssh on hostgator vps with node / npm / mongodb

Hi all,
I know this isn't related to script or code but i'm having a hell of a time with my vps and getting node.js and mongo working correctly on my hostgator vps. If anyone can assist me I'd greatly appreciate it. I have installed nodejs and mongodb through 'yum install nodejs' then npm mongodb' and I can even start 'mongod'. When I close my terminal and reopen it, I can't reach 'mongo', 'npm' or 'node' it returns with "command not found" but if I run 'sudo reboot' all the above commands work!? Can anyone explain this to me and provide advice?

Thanks!

**EDIT**I realized when I run "sudo reboot" while logged into ssh it kicks me back to my local terminal environment..that's why my commands were working. So my original problem remains.. I lose my commands/installs after closing out of my ssh connection