FreeBSD Vim在Insert模式下，上下左右箭头键显示为ABCD四个字母。
解决：
方法1.
编辑.vimrc，加入set nocompatible
方法2.
$ vim ~/.vimrc
set t_ku= (now type Ctrl-V and press cursor up)
set t_kd= (now type Ctrl-V and press cursor down)
set t_kr= (now type Ctrl-V and press cursor right)
set t_kr= (now type Ctrl-V and press cursor left)
You should get something that looks like
set t_ku=^[OA
set t_kd=^[OB
set t_kr=^[OC
set t_kl=^[OD
