Centos 6 rvm不工作

Question

我面临着rvm在centos 6中的问题。它工作正常，直到我安装了nvm。我收到以下错误：

ERROR: Missing proper 'which' command. Make sure it is installed before using RVM!
WARNING:
      Errors sourcing '/usr/local/rvm/scripts/base'.
      RVM will likely not work as expected.