How do I copy one character at a time from the line above or below while typing in insert mode?

Explanation

In insert mode, <C-e> copies the character directly below the cursor (from the next line) and <C-y> copies the character directly above (from the previous line). Holding either key streams characters column by column from the adjacent line — without leaving insert mode or disrupting the current line.

How it works

• The character is taken from the same column position on the adjacent line
• Each keypress copies exactly one character and advances the cursor one position
• The adjacent line is not modified
• Note: in normal mode, <C-e> and <C-y> scroll the viewport — this is a separate, insert-mode-only behavior

Example

You have two similar lines and are typing the second:

const CONFIG_PATH = "/etc/app/config.json";
const LOG_PATH = "

With the cursor after the opening quote, pressing <C-y> repeatedly copies /etc/app/ character by character from the line above, saving you from retyping the common prefix.

Tips

• Unlike <C-n>/<C-p> word completion, these keys copy raw characters with no menu or selection step
• Works across line endings: if the line above is shorter, Vim stops copying when it runs out of characters
• Combine with <C-e> to pull from below when writing header/footer pairs
• Great for duplicating URLs, import paths, or any repeated structural prefix