Linux server sudo command not foundrubylinuxbashserversudo

Question

I am having Linux server with

2.6.32-673.8.1.lve1.4.3.el6.x86_64 - GNU/Linux

and trying to run following commands :

 sudo apt-get update

-bash: sudo: command not found

I have also tried - sudo su

-bash: sudo: command not found

And for lsb_release -a

-bash: lsb_release: command not found

I am trying to install ruby. Any help is highly appreciated.