The latest upgrade of Ubuntu made my vim colorscheme unusable. I know how to set it manually (:colo evening, for example), but I want to set the default for all
Your .vimrc file goes in your $HOME directory. In *nix, cd ~; vim .vimrc. The commands in the .vimrc are the same as you type in ex-mode in vim, only without the leading colon, so colo evening would suffice. Comments in the .vimrc are indicated with a leading double-quote.
To see an example vimrc, open $VIMRUNTIME/vimrc_example.vim from within vim
:e $VIMRUNTIME/vimrc_example.vim
It's as simple as adding a line to your ~/.vimrc:
colorscheme color_scheme_name
Ubuntu 17.10 default doesn't have the ~/.vimrc file, we need create it and put the setting colorscheme color_scheme_name in it.
By the way, colorscheme desert is good scheme to choose.
Put a colorscheme directive in your .vimrc file, for example:
colorscheme morning
See here: http://vim.wikia.com/wiki/Change_the_color_scheme