nved

README

nved

A small terminal text editor that feels like a REPL rather than a full-screen application. You print a range of lines by number, climb into the printed block with the arrow keys, and edit it in place. There is no alternate screen and no takeover of your terminal: output scrolls normally and your scrollback stays intact, the way cat or an old line editor leaves it.

nved is a from-scratch descendant of ved, an ed clone. Where ved replays commands against text, nved lets you move a real cursor through committed lines and change them directly. It is deliberately small and single-purpose — one window, one buffer — and best suited to dialing in a specific part of a file by line number, not to scrolling through large files.

Install

On Debian or Ubuntu, add the Excelano apt repository once and updates flow through apt upgrade:

curl -fsSL https://excelano.com/apt/setup.sh | sudo sh
sudo apt install nved

With a Go toolchain:

go install github.com/excelano/nved@latest

Build from source

git clone https://github.com/excelano/nved
cd nved
go build -o nved .

Requires Go 1.25 or newer.

How it works

Start nved with a file name, or with no argument for an empty unnamed buffer. At the > prompt you address lines by number:

Command	Effect
N	print line N
N.M	print lines N through M
N.	print from line N to the end
.N	print from the start to line N
.	print the whole file
$	print the last line
$-N	print the Nth line before the last
head [N]	print the first screenful, or the first N lines
tail [N]	print the last screenful, or the last N lines
s [name]	save; a name is required when unnamed (also Ctrl+S)
x	exit; warns once when dirty (also Ctrl+X, q, quit)
h	show the command and key reference (also H, ?)

The . separator sits under the right hand on the numeric keypad, where there is no comma; a , works in its place anywhere — the two are interchangeable.

A number can be offset from the end with $-N, so $-9.$ is the last ten lines. tail is the everyday shorthand for that: bare tail brings the last screenful on screen ready to climb into, and tail 10 shows the last ten lines. head is its mirror at the top. The offset is ed's address arithmetic, restricted to the $ anchor since nved has no roaming current line.

You can also open straight to a range. A +spec argument — spec is any of the commands above — runs once on startup, so the block is already on screen at the prompt:

nved +42 notes.txt        # open with line 42 printed
nved +10.30 notes.txt     # ... lines 10 through 30
nved +tail notes.txt      # ... the last screenful, ready to edit

Out-of-range numbers clamp to the nearest valid line. A range taller than the terminal prints one screenful from the top; Page-Up and Page-Down reprint the screenful above or below so you can walk through it.

The printed block sits just above the prompt. Climb into it to edit:

• Up lands on the bottom line, Left at the end of the last line, Ctrl+Home on the first line.
• Arrows move the cursor; Ctrl+Left / Ctrl+Right skip by words; Home / End and Ctrl+Home / Ctrl+End jump to the edges.
• Enter splits a line, Backspace and Delete join lines, typing inserts.
• Ctrl+U undoes the last edit. The history lives with the buffer, so it works at the > prompt too and survives climbing in and out — if the undone edit has scrolled off, nved reprints it.
• Ctrl+S saves in place without leaving (your cursor stays put); Ctrl+X exits — the save and exit chords work while editing, just as at the prompt.
• Leave the editor with Esc or Ctrl+C, or by stepping off the bottom (Down) or off the end of the last line (Right) — the mirror of how you climbed in.

Long lines are word-wrapped by nved itself, with a continuation indent that lines the wrapped text up under the gutter. Edits stay inside the printed block; to edit elsewhere, print that range and climb into it.

Viewing delimited files (CSV, TSV, DSV)

A .csv is a text file, so nved opens it as plain text — nothing happens until you ask. Set a delimiter and the printed block renders as aligned columns:

> csv

csv is a preset; underneath it are independent switches you can set or tune on their own:

Command	Effect
dsv C	split each line into columns on C — a character, or the name tab or unit
dsv off	back to plain text
quotes on|off	respect "quoted,fields" when splitting
headers on|off	draw line 1 as a faint column header, pinned when it scrolls off
rows newline|record	the record separator (record is the ASCII record separator, 0x1E)
csv tsv asv	presets — csv is dsv , with quotes and headers on, tsv the same with tabs, asv the ASCII-separated set (unit fields, record rows)

Each switch invoked bare — dsv, quotes, headers, rows — reports its current state instead of changing it. Columns are sized to the widest cell on screen, and a row wider than the terminal is truncated at the right edge with a marker.

The two ASCII information separators are worth knowing: unit (0x1F) for fields and record (0x1E) for rows never occur in ordinary text, so a file delimited by them needs no quoting or escaping at all — asv is the one-word way to read one.

Because the view is reached through ordinary commands, +spec opens straight into it:

nved +csv data.csv
nved +asv data.bin

The aligned view is read-only in this version: to edit, dsv off back to plain text, change the values, then set the delimiter again. Aligned editing — moving the cursor cell to cell — is the next step.

License

MIT — see LICENSE. Authored by David Anderson, with AI assistance.

Documentation

Overview

Command nved is a REPL-flavored terminal text editor — "new ved".

Slice 2: the editor core. On top of slice 1's command REPL it adds climbing into the most-recently-printed block to edit it in place — cursor movement, insert, Enter-split, Backspace/Delete-join — with ANSI block redraw over the real (scrolling) terminal rather than an alternate screen.