Special Registers
"/ ": ". "% "# "= "_ — the read-only and weird ones.
Vim provides several read-only registers that contain useful state: "/ is the last search, ": the last Ex command, ". the last inserted text, "% the current filename, "# the alternate file, "= the expression register, and "_ the black hole.
Beyond the alphabetic and numbered registers, Vim has a small zoo of special registers. Most are read-only — Vim writes to them automatically as you work, and you read from them when useful.
| Register | Holds | Useful for |
|---|---|---|
| "/ | Last search pattern | Reusing search in :s |
| ": | Last Ex command | Pasting it to edit and re-run |
| ". | Last inserted text | Re-typing the last Insert content |
| "% | Current filename | Inserting it in commands or buffer |
| "# | Alternate (previous) filename | Switch-to-other-file shortcut |
| "= | Expression register (interactive) | Insert computed values |
| "_ | Black hole — write-only, discards text | Delete without clobbering registers |
See also: Registers, Special Registers Deep Dive, Pattern Search, Substitute (:s)