1.gem executables will not run
WARNING: You don't have /Users/hexincaifu/.gem/ruby/2.3.0/bin in your PATH,
gem executables will not run.
解决路径环境变量
export PATH="/Users/hexincaifu/.gem/ruby/2.3.0/bin:$PATH
https://askubuntu.com/questions/406643/warning-you-dont-have-a-directory-in-your-path-gem-executables-will-not-run
2.While executing gem ..(Gem::FilePermissionError)
解决用下面命令代替sudo
gem install mygem --user-install
https://stackoverflow.com/questions/14607193/installing-gem-or-updating-rubygems-fails-with-permissions-error