The MobaXterm application for Windows is a good way to practice Linux commands if you are stuck on a Windows only machine. This application is extensible with add ons such as the gcc compiler and Vim editor as well as many other add ons to make the application even more useful. This is good for practising programming as well; since you can add the gcc compiler and start programming straight away. I recommend this as you can copy it on to your thumb drive and take it somewhere else and run it there to practice Bash commands and C programming. The fact that this exists is awesome, and it is better than installing Cygwin due to the fact that you can run it anywhere and it is a better command-line than the Powershell or cmd DOS shell that Windows 7 includes. So there is no need to run Ubuntu or Mint in a Virtualbox session if you just want to practice Linux commands and get used to the shell.