How do I capture command-line output directly into a register?

Explanation

When debugging a session or building repeatable edits, it is useful to turn command output into editable text. Vim's :redir can redirect Ex command output into a register, which gives you a fast bridge from transient command-line information to normal-mode operations. This is powerful for advanced workflows where you want to inspect, transform, or paste diagnostic output without leaving Vim.

How it works

• :redir @a starts redirecting command output into register a
• | chains commands on one Ex line
• messages prints the message history
• | redir END stops redirection and finalizes register contents

After this runs, register a contains the same text you would normally only see in the command area. You can inspect it with :reg a, paste it with "ap, or process it further.

Example

Run:

:redir @a | messages | redir END

Then paste the captured output into a scratch buffer:

"ap

Resulting text might look like:

Error detected while processing ...
line 12: E121: Undefined variable

Tips

• Use uppercase register names (for example @A) if you want to append multiple captures into one log register.
• Swap messages for other commands that print useful output and keep the same redirection pattern.