When you want ssh to an linux server, you have many softwares which help you ssh to server such as PuTTy, WinSCP... But most of them running on windows client.
On MacOS X. An SSH client is included by default with all Mac OS X installations.

To access the Mac OS X SSH client, open a Terminal window and run ssh:
  1. Open your Macintosh HD
  2. Navigate to the Applications folder
  3. Select Utilities
  4. Locate the Terminal icon
  5. Click the Terminal icon to access your Mac OS X terminal
  6. Enter ssh -l USERNAME SERVER_IP_OR_DOMAIN into the terminal window (where USERNAME is your username and SERVER_IP_OR_DOMAIN is the IP or domain name associated with your VPS) to open an SSH session
  7. Start control your linux server using linux commands.