来源：http://superuser.com/questions/300500/ubuntu-unable-to-edit-bashrc-file-because-of-readonly

This is a vim issue, not a file permission issue. If you did not have read permission on the file, you'd see a "Permission denied" error.

Do you invoke vi/vim with the -R option? Are you calling view instead of vi or vim? Do you have set readonly in your .vimrc or in a file in ~/.vim/ftplugin?

In vim you can enter :set noreadonly to unset the readonly flag.

步骤：

1.按Esc键

2.输入  :set noreadonly

3.然后就能正常保存了，你可以输入 :wq 来保存文件了。

转自:http://blog.csdn.net/longerandlonger/article/details/7266055