cless 0.0.2

A less-like terminal pager with tree-sitter syntax highlighting
cless-0.0.2 is not a library.

cless

A less-like terminal pager with tree-sitter syntax highlighting.

Features

  • less-compatible keybindings: number-prefix counts (5j, 100G, 50%), line / page / half-page motion, top / bottom / percent jumps, horizontal scroll
  • Search: /pattern and ?pattern, repeat with n / N, smart-case (all-lowercase pattern is case-insensitive), matches shown in reverse video
  • Tree-sitter highlighting for 15 languages: Rust, Python, JavaScript, TypeScript (incl. TSX), JSON, Go, Bash, TOML, YAML, HTML, CSS, C, Markdown
  • citruszest palette (from zootedb0t/citruszest.nvim) emitted as truecolor ANSI
  • Language detection: file extension → special filenames (.bashrc etc.) → shebang

Installation

Recommended: cargo binstall (downloads a prebuilt binary, no C toolchain needed)

cargo binstall cless

This pulls a prebuilt binary from GitHub Releases. Supported targets: x86_64-unknown-linux-gnu / aarch64-unknown-linux-gnu / x86_64-apple-darwin / aarch64-apple-darwin / x86_64-pc-windows-msvc.

If you don't have cargo-binstall yet: cargo install cargo-binstall.

Building from source

cargo install --path .
# or
cargo build --release   # target/release/cless

Building from source requires a C compiler because each tree-sitter parser is written in C (macOS: xcode-select --install, Ubuntu: apt install build-essential). The release binary is ~10 MB.

Usage

cless <file>

Keybindings

 Movement
   j, ↓, ENTER, ^E, ^N       one line down
   k, ↑, ^Y, ^P               one line up
   SPACE, f, ^F, ^V, PgDn    one window down
   b, ^B, PgUp                one window up
   d, ^D                      half-window down
   u, ^U                      half-window up
   g, <, HOME                 first line   ([N]g jumps to line N)
   G, >, END                  last line    ([N]G jumps to line N)
   p, %                       [N] percent into the file
   ←, →                       horizontal half-screen scroll

 Searching
   /pattern                   search forward
   ?pattern                   search backward
   n                          repeat last search
   N                          repeat in the reverse direction

 Other
   =, ^G                      show current file position
   r, R, ^L                   repaint the screen
   h, H                       help screen
   q, Q, ZZ, ^C               quit

Number prefix: most movement keys accept a repeat count or line number (e.g. 5j, 100G, 30%).

Customising the palette

Colors are defined as FG_* constants at the top of src/highlight.rs, and color_for(name) maps tree-sitter capture names (keyword, function, string, ...) to those colors. Edit and rebuild to change the theme.

The 26 supported capture names live in HIGHLIGHT_NAMES and follow the standard tree-sitter / Neovim naming conventions.

Architecture

File Role
src/main.rs Arg parsing and error handling
src/highlight.rs Language detection + tree-sitter; builds Vec<Line>
src/pager.rs Terminal control (crossterm), input loop, search, rendering

Limitations

  • No stdin / pipe input (file argument only)
  • Cannot open binary or non-UTF-8 files
  • Not implemented: F (tail -f mode), m/' marks, -N line numbers, multi-file (:n)
  • No theme-switch flag (color changes require a rebuild)

License

Dual-licensed under MIT or Apache-2.0; users may choose either (Rust ecosystem standard).

SPDX identifier: MIT OR Apache-2.0

Contributions

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in this repository shall be dual-licensed as above, without any additional terms or conditions.