Registers and the Clipboard

Working Code

Open this code in Vim:

const firstName = "Alice";
const lastName = "Kim";
const fullName = firstName + " " + lastName;

1. On the first line, press yy to yank the line.
2. On the second line, press dd to delete the line.
3. Press p — you paste the line you deleted with dd, not the one you yanked.

Why? Because dd overwrote the default register. In Vim, delete also saves to a register. To fix this, you need to understand registers.

Try It Yourself

Using the same code, try a named register this time:

const firstName = "Alice";
const lastName = "Kim";
const fullName = firstName + " " + lastName;

1. On the first line, press "ayy — yank the line into register a.
2. On the second line, press dd — delete the line (goes into the default register).
3. Press "ap — paste from register a. The first line is pasted correctly.

"a is a prefix meaning "use register a." It's like putting a label on a drawer.

"Why?"

Registers are drawers

A regular editor has only one clipboard. Copy something new, and the previous content vanishes. Vim has many drawers (registers) so you can hold multiple pieces of text at once.

Types of registers

Default register ("") vs. yank register ("0)

This distinction matters:

yy  → stored in both "" and "0
dd  → stored in "" only (doesn't touch "0)

So if you yank with yy, then delete another line with dd, you can still paste the yanked content with "0p. Register "0 remembers only yanked (y) content.

Using named registers

You have 26 named registers from "a to "z:

"ayy    → yank the current line into register a
"bdd    → delete (store) the current line into register b
"ap     → paste from register a
"bp     → paste from register b

Use an uppercase letter to append to the existing content:

"ayy    → store the first line in register a
"Ayy    → append the second line to register a

Inspect registers

Run :registers (or :reg) to see the contents of all registers:

:reg        " show all registers
:reg a      " show only register a
:reg ab0    " show registers a, b, and 0

System clipboard integration

To move text between Vim and other apps, use the "+ register:

"+y     → yank to system clipboard (Vim → browser)
"+p     → paste from system clipboard (browser → Vim)
"+yy    → yank the current line to system clipboard

Use it to paste code from a browser into Vim, or from Vim into Slack.

Black hole register ("_)

Delete something without polluting registers:

"_dd    → truly delete the current line (saved nowhere)
"_diw   → truly delete a word

Useful when you want to preserve a previously yanked value while removing unwanted text.

Deep Dive

third = "C"
first = "A"
second = "B"

first = "A"
second = "B"
third = "C"