How do I append text with :normal without creating an extra undo step?

Explanation

When you automate edits from Ex commands, Vim usually creates a separate undo entry for each change. :undojoin lets you merge the next change into the previous undo block, so one u reverts the whole scripted operation. This is especially useful in mappings, command-line workflows, and one-off refactors where you want atomic undo behavior.

How it works

• :undojoin tells Vim to join the next change with the previous undo step
• | chains another Ex command on the same command-line
• normal! A; runs a Normal-mode append-at-end (A) and inserts ;

A key detail: :undojoin only works if there was a change immediately before it. If no prior undoable edit exists, Vim raises an error instead of silently creating a new block.

Example

Suppose you run one scripted append, then a second append joined with :undojoin:

:normal! A,
:undojoin | normal! A;

Before:

result = value

After both commands:

result = value,;

Pressing u once reverts both scripted appends together, not one-by-one.

Tips

• Use this in custom commands when multiple edits should feel like one action
• Prefer normal! (with !) so mappings do not interfere
• If you see an :undojoin error, run it only after a successful change