自升级到Mac OSX 10.10以来，从R控制台运行系统命令无法找到已安装的程序

I have been having some weird issues with R (3.1.1) and RStudio (0.98.1079) and I suspect that it is due to the fact that these programs are not longer referencing the right places after I upgraded to Mac OSX 10.10. with R (3.