Bash在重新安装后无法找到ghc？

Drews-MACBook-Pro:Blokus-AI drewgross$ghc
-bash: /usr/local/bin/ghc: No such file or directory

知道为什么吗？我怀疑这与我的道路或类似事情有关,但我还没有发现任何奇怪的东西.我可以直接使用ghc：

Drews-MACBook-Pro:Blokus-AI drewgross$/usr/bin/ghc
ghc: no input files
Usage: For basic information,try the `--Help' option.

/usr/bin /在我的路径中：

Drews-MACBook-Pro:Blokus-AI drewgross$echo $PATH
/Users/drewgross/.rvm/gems/ruby-1.9.3-p327/bin:/Users/drewgross/.rvm/gems/ruby-1.9.3-p327@global/bin:/Users/drewgross/.rvm/rubies/ruby-1.9.3-p327/bin:/Users/drewgross/.rvm/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/local/git/bin

我还可以做些什么？