CentOS6 root 用户 vi/vim 无法开启高亮

if [ -n "$BASH_VERSION" -o -n "$KSH_VERSION" -o -n "$ZSH_VERSION" ]; then
  [ -x /usr/bin/id ] || return
  ID=`/usr/bin/id -u`
  [ -n "$ID" -a "$ID" -le 200 ] && return
  # for bash and zsh, only if no alias is already set
  alias vi >/dev/null 2>&1 || alias vi=vim
fi