I installed gfortran 90 when I wanted gfortran 77, which is causing errors in configuring mpich, so as such I wanted to uninstall gfortran 90 from my computer, but deleting gfortran from usr/local/bin didn't really do anything. When I do gfortran -v I get an answer, when I want something like bash: command not found. How can I do that?
From : http://www.webmo.net/support/fortran_osx.html
Thus, to uninstall the package, run
$ sudo rm -r /usr/local/gfortran /usr/local/bin/gfortran
Edit: There also other methods, it apparently depends of the package you've installed to get it.