nem

nem

A terminal text editor with nano's shape and emacs's keybindings.

One file, one screen, no modes — but C-f moves forward, C-k kills a line, C-x C-s saves, and the kill ring behaves the way your fingers expect.

 1 package main                      │  1 # notes
 2                                   │  2
 3 import "fmt"                      │  3 - ship the thing
 4                                   │  4 - write it down
 5 func main() {                     │  5
 6     // say hello                  │
 7     fmt.Println("hi", 42)         │
 8 }                                 │
▍main.go  go  ⎇ main ──────── 7:26  │  notes.md  md ──────── 3:0
Wrote main.go

Code is coloured, line numbers sit outside the text so they can never be selected, and the status line carries the file type and git branch. It keeps your terminal's own background rather than painting over it.

Install

Download a binary for your platform from the latest release, or:

go install github.com/Borderliner/nem/cmd/nem@latest

From source:

git clone https://github.com/Borderliner/nem
cd nem && make build
./nem file.txt

Go 1.27 or later, and nothing else.

make build sets CGO_ENABLED=0, which matters: Go turns cgo on by default when a C compiler is present, and a dependency pulls in os/user, which links libc for NSS lookups. With it off the binary is fully static — no libc, no glibc version skew, runs on musl and Alpine — and strips to about 5 MB. A plain go build still works but gives you a dynamically linked binary.

Being cgo-free is also why every platform cross-compiles from any other, so releases for Linux, macOS and Windows on both amd64 and arm64 all come off one machine. Windows binaries are published but lightly tested; state lives under %LOCALAPPDATA% there rather than the XDG path used elsewhere.

What it does

Editing — the emacs motion and editing set: C-f/C-b/C-n/C-p, M-f/M-b, C-a/C-e, M-</M->, C-d, C-k, M-d, C-t, M-u/M-l/M-c. Cursor motion stops at grapheme boundaries, so a decomposed é or a ZWJ family emoji is one press, not seven.

Mark and kill ring — C-SPC sets the mark, C-w kills the region, M-w copies it, C-y yanks and M-y rotates. Consecutive kills accumulate into one entry, so C-k C-k then C-y gives you back what you took. Backward kills prepend, so M-DEL M-DEL over "foo bar" yanks as foo bar, not bar foo.

Buffers and windows — C-x C-f find file, C-x b switch buffer, C-x 2/C-x 3 split, C-x o move between windows. Two windows onto one buffer keep independent cursors and viewports.

Search — C-s is genuinely incremental: it moves as you type, backspace walks point back, and C-g returns you to where you started. M-% is query-replace with y/n/!/q.

Prefix keys, M-x, and C-u — C-x is a real prefix keymap, M-x completes over every command by name, and C-u takes numeric and negative arguments.

Undo — linear undo and redo (C-/ and M-_). Typing coalesces into one undo unit; a new edit after undoing discards the redo branch.

Help — <f1> b lists every binding, <f1> k describes a key. Pause on a prefix like C-x and a panel shows everything that can follow it.

Completion — M-x, C-x C-f and C-x b open a centred panel that filters as you type, fuzzily: fwc finds forward-char. Matched characters are highlighted so you can see why something matched.

Line numbers — shown by default, and drawn outside the text so they can never be selected or copied. C-x n toggles them.

Syntax highlighting — Go, Lua, JSON and Markdown have hand-written lexers; C, Python, shell, Rust, JavaScript, TypeScript, YAML, TOML, HTML, CSS, SQL, Makefile, Dockerfile, XML and INI are bundled into the binary. If nano happens to be installed, its definitions add about forty more. Nothing needs installing.

Selection — C-SPC marks, and the region is visible. Typing replaces it, Backspace deletes it, and that undoes in one step.

Moving text — M-<up> and M-<down> move the current line, or every line the region covers, keeping the selection so the key repeats.

Your work is kept — a backup of the previous contents on first save, an autosave every 30 seconds while modified, and a refusal to overwrite a file that changed on disk underneath you. Nothing is written beside your file; it all goes under ~/.local/state/nem.

C-h is bound to help too, but only works on terminals that negotiate the extended keyboard protocol. On older terminals the terminal itself cannot tell C-h from Backspace before nem sees it. Use <f1>.

Configuration

~/.config/nem/init.lua is a real Lua script, not a config format:

nem.set("tab-width", 4)
nem.bind("<f5>", "save-buffer")

nem.command("strip-trailing-space", "Remove trailing whitespace everywhere.",
  function()
    for i = 1, nem.buf.line_count() do
      nem.buf.set_line(i, (nem.buf.get_line(i):gsub("%s+$", "")))
    end
  end)
nem.bind("C-c w", "strip-trailing-space")

nem.hook("before-save", function(buf)
  if buf.path:match("%.go$") then nem.run("strip-trailing-space") end
end)

Commands you define are registered alongside the built-ins, so M-x finds them and <f1> k describes them. Line numbers are 1-based, and anything a script changes is undoable with C-/. A broken config never takes the editor down — the error lands in the echo area and nem carries on with defaults.

Scripts get string, table and math, but not io or os, so a hook cannot shell out to an external formatter. A formatter written in Lua against nem.buf works.

See docs/config.md.

Not yet

Syntax highlighting · mouse support · line wrapping (long lines truncate with $ and scroll horizontally) · undo tree · multi-line search patterns

Design

Layered so the hard parts are testable without a terminal:

Two decisions worth knowing. The minibuffer is a real buffer in a real window, as in emacs, so C-a/C-e/C-k and the kill ring work inside prompts with no extra code, and M-x, C-s, find-file and query-replace are all callers of one mechanism. And commands never reach the screen — they act through an interface, which is why the whole command layer is tested headlessly.

The full design, including the decisions that were rejected and why, is in docs/design/2026-09-18-nem-design.md.

Licence

MIT — see LICENSE.

Released binaries are statically linked and so contain the permissively licensed libraries listed in THIRD-PARTY.md. nem reads nano's syntax definitions from the system when they are present but never distributes them; the rules it bundles are its own.