nn

A terminal-based text editor written in Go, inspired by nano. Arrow-key navigation, clipboard operations, syntax highlighting, search, undo/redo, fuzzy file finder, file sidebar, git integration, and multi-theme support.

Built with tview and tcell.

Build

go build -o nn .

Requires Go 1.24+.

Run

./nn              # start with empty buffer
./nn file.txt     # open existing file

Key Bindings

Global (editor + sidebar)

Key	Action
F1	Open help popup
Ctrl+P	Fuzzy file finder
Ctrl+S	Save file
Ctrl+N	New file
Ctrl+B	Toggle / hide sidebar
Ctrl+R	Toggle hidden files in sidebar
Ctrl+Q	Quit
Alt+T	Cycle theme
Alt+← / →	Switch tabs
Shift+Alt+← / →	Resize sidebar

Editor mode

Key	Action
Ctrl+F	Search (Tab/Shift+Tab to cycle matches)
Ctrl+Z / Ctrl+Y	Undo / Redo
Ctrl+O	Open file
Ctrl+C / V / X	Copy / Paste / Cut
Ctrl+A	Select all
Ctrl+D	Duplicate line
Ctrl+/	Toggle comment
Ctrl+W	Close tab
Ctrl+T	Reveal current file in sidebar
↑ ↓ ← →	Move cursor
Shift+↑ ↓ ← →	Extend selection
Ctrl+← / →	Word jump
Home / End	Start / end of line
Page Up / Page Down	Scroll page
Enter	Newline
Backspace	Delete backward
Delete / Shift+Delete	Delete forward / delete line
Tab / Shift+Tab	Indent / unindent (selection)
Escape	Clear selection

File sidebar

Key	Action
↑ / ↓	Navigate files
Enter	Open file / enter directory
←	Go to parent directory
→	Enter directory
Ctrl+F	Filter files by name
Delete	Delete selected file (with confirmation)
Escape	Clear filter / switch to editor
Tab	Switch to editor
Home / End	First / last entry
Page Up / Page Down	Scroll page

Search mode (Ctrl+F in editor)

Key	Action
Tab	Next match
Shift+Tab	Previous match
Enter / Escape	Close search

File filter mode (Ctrl+F in sidebar)

Key	Action
↑ / ↓	Navigate filtered list
Enter	Open selected file
Escape	Cancel filter

Fuzzy File Finder (Ctrl+P)

Opens a searchable overlay to quickly jump to any file in the project tree.

• Start typing to filter files by name
• ↑ / ↓ to navigate results
• Enter to open the selected file
• Escape to cancel

Fuzzy matching scores files by consecutive character matches and word boundaries, with depth and dependency-directory penalties. Results are ranked and capped at 200.

Syntax Highlighting

Chroma-based highlighting for: Go, Python, JavaScript, TypeScript, JSX, Rust, C/C++, Java, Ruby, Bash, YAML, JSON, TOML, Markdown, HTML, CSS, SQL, PHP, XML (and SVG, XSL), Lua, Zig, Swift, Kotlin, Scala, Elixir, R, Svelte, Vue, Protocol Buffers, Terraform, Dockerfile, Nix, Fish, OCaml, and more.

Themes

Key	Action
Alt+T	Cycle through available themes

Available themes: Catppuccin Mocha, Catppuccin Latte, Tokyo Night, Tokyo Night Day, Dracula, One Dark, Ayu Light, Gruvbox Dark.

Theme, dotfiles preference, and sidebar width are persisted to ~/.config/nn/settings.json on quit.

Settings

Persisted to ~/.config/nn/settings.json:

• theme — last selected theme name
• hide_dotfiles — whether hidden files are shown in the sidebar
• sidebar_width — sidebar width in characters

Sidebar

• File tree navigation with arrow keys and Enter
• Filter files by name with Ctrl+F
• Directory position memory (remembers your scroll position per directory)
• Delete files with Delete (with confirmation prompt)
• Toggle hidden files with Ctrl+R (hidden by default)
• Resize with Shift+Alt+← / → (clamped 15–60)

Status Bar

Shows mode indicator (EDITOR / SIDEBAR), filename (• when modified), transient messages (green background), F1 help hint, git branch, and cursor position (row:col). Press F1 for the full keybinding reference.

Git Integration

• Git status computed via pure Go (go-git/v5), no external git binary
• Branch name shown in the status bar as @branch
• Sidebar filenames colored by git status:
  • Red — untracked or deleted
  • Orange — modified (or unsaved active file)
  • Green — staged/added
• Editor gutter shows a thin bar indicator (▎) per line:
  • Orange — line modified
  • Green — line added
  • Gray — unchanged
• Line-level diff uses LCS (longest common subsequence) for accurate markers
• Git status refreshes on save, file open, tab switch, undo/redo, and every 10 seconds via background ticker

Mouse

• Click in editor to position cursor
• Click in sidebar to select file (then press Enter to open)
• Scroll wheel: scrolls editor / navigates sidebar