[Practical.Vim(2012.9)].Drew.Neil.Tip08学习摘要

Chunk Your Undos

The u key triggers the undo command, which reverts the most recent change.
A change could be anything that modifies the text in the document. That includes commands triggered from Normal, Visual, and Command-Line modes, but a change could also encompass any text entered (or deleted) in Insert mode. So we could also say that i{insert some text}<Esc> constitutes a change.

在vim中u命令执行undo命令，撤销最近一次的改变。改变可以是任何对文本的修改。包括Normal模式下的修改，也可以是Visual模式，Insert模式下的添加删除文本修改。所以 i{insert some text}<Esc>构成了一个改变。