我知道在 Vim 中可以输入一个命令或类似的东西，它的作用与大多数 GUI 程序中的CTRL+相同Z，可以撤消刚刚输入的内容，但我记不清它是什么了。有人知道吗？
答案1
从帮助vim：
<Undo> or *undo* *<Undo>* *u*
u Undo [count] changes. {Vi: only one level}
*:u* *:un* *:undo*
:u[ndo] Undo one change. {Vi: only one level}
*E830*
:u[ndo] {N} Jump to after change number {N}. See |undo-branches|
for the meaning of {N}. {not in Vi}
*CTRL-R*
CTRL-R Redo [count] changes which were undone. {Vi: redraw
screen}
*:red* *:redo* *redo*
:red[o] Redo one change which was undone. {Vi: no redo}
*U*
U Undo all latest changes on one line, the line where
the latest change was made. |U| itself also counts as
a change, and thus |U| undoes a previous |U|.
{Vi: while not moved off of the last modified line}
The last changes are remembered. You can use the undo and redo commands above
to revert the text to how it was before each change. You can also apply the
changes again, getting back the text before the undo.
The "U" command is treated by undo/redo just like any other command. Thus a
"u" command undoes a "U" command and a 'CTRL-R' command redoes it again. When
mixing "U", "u" and 'CTRL-R' you will notice that the "U" command will
restore the situation of a line to before the previous "U" command. This may
be confusing. Try it out to get used to it.
The "U" command will always mark the buffer as changed. When "U" changes the
buffer back to how it was without changes, it is still considered changed.
Use "u" to undo changes until the buffer becomes unchanged.
==============================================================================
2. Two ways of undo *undo-two-ways*
How undo and redo commands work depends on the 'u' flag in 'cpoptions'.
There is the Vim way ('u' excluded) and the Vi-compatible way ('u' included).
In the Vim way, "uu" undoes two changes. In the Vi-compatible way, "uu" does
nothing (undoes an undo).
'u' excluded, the Vim way:
You can go back in time with the undo command. You can then go forward again
with the redo command. If you make a new change after the undo command,
the redo will not be possible anymore.
'u' included, the Vi-compatible way:
The undo command undoes the previous change, and also the previous undo command.
The redo command repeats the previous undo command. It does NOT repeat a
change command, use "." for that.
Examples Vim way Vi-compatible way ~
"uu" two times undo no-op
"u CTRL-R" no-op two times undo
Rationale: Nvi uses the "." command instead of CTRL-R. Unfortunately, this
is not Vi compatible. For example "dwdwu." in Vi deletes two
words, in Nvi it does nothing.
==============================================================================
3. Undo blocks *undo-blocks*
One undo command normally undoes a typed command, no matter how many changes
that command makes. This sequence of undo-able changes forms an undo block.
Thus if the typed key(s) call a function, all the commands in the function are
undone together.
If you want to write a function or script that doesn't create a new undoable
change but joins in with the previous change use this command:
*:undoj* *:undojoin* *E790*
:undoj[oin] Join further changes with the previous undo block.
Warning: Use with care, it may prevent the user from
properly undoing changes. Don't use this after undo
or redo.
{not in Vi}
This is most useful when you need to prompt the user halfway through a change.
For example in a function that calls |getchar()|. Do make sure that there was
a related change before this that you must join with.
This doesn't work by itself, because the next key press will start a new
change again. But you can do something like this: >
:undojoin | delete
After this an "u" command will undo the delete command and the previous
change.
To do the opposite, break a change into two undo blocks, in Insert mode use
CTRL-G u. This is useful if you want an insert command to be undoable in
parts. E.g., for each sentence. |i_CTRL-G_u|
Setting the value of 'undolevels' also breaks undo. Even when the new value
is equal to the old value.
:help undo当你在 时，你可以找到休息vim。