baeru

Make existing terminal commands look excessive on purpose.

About

baeru is a Rust wrapper for existing terminal applications and command output. It adds animation, color transformation, highlight reactions, and command-specific input behavior without patching the target application itself.

It is intentionally not a minimal utility. The goal is to take existing commands like htop, lazygit, ls, or journalctl and make them feel theatrical.

At the moment, baeru focuses on:

cinematic TUI startup reveals
live ANSI recoloring
per-command key remapping
inline animation for ordinary CLI output
regex-driven highlight reactions
profile-driven behavior from baeru.yml

Note

baeru is still a PoC, but the project direction is clear: this repository is for making existing commands louder, flashier, and more animated.

Releated project

This repository focuses on expressiveness. While the ability to wrap and modify existing TUI applications has many potentials, this application focuses on "making existing TUI applications more flashy." We have also prepared another repository for testing more practical features, so please check that out as well if you're interested.

baeru Built for animation, showy wrapping, and command-level visual experiments
twrap A more practical TUI-focused extraction for the terminal wrapping layer itself

If you want the production-oriented TUI wrapper path without the whole "make it glow" direction, twrap is the place to look.

First look

TUI reveal + live color

profiles:
  - name: htop-jirai-pink
    match:
      command: htop
    backend: tui
    features:
      - reveal
      - live_color
    effect: coalesce
    effect: scatter
    theme_file: examples/themes/jirai-pink.yml
    capture_ms: 360
    duration_ms: 1120
    frames: 24

TUI reveal + live color + live rendor + realtime masking + highligh text + charactor fade

profiles:
  - name: htop-jirai-pink
    match:
      command: htop
    backend: tui
    features:
      - reveal
      - live_color
      - live_render
    effect: scatter
    animation_color_fade: true
    animation_color_darken_factor: 0.02
    live_render_duration_ms: 620 # The fade is slowed down to make it easier to see.
    live_render_mouse_quiet_ms: 280
    theme_file: examples/themes/jirai-pink.yml
    capture_ms: 360
    duration_ms: 1120
    frames: 24

CLI inline animation + theme

  - name: ls-inline
    match:
      command: ls
    backend: cli
    features:
      - inline_animation
    effect: coalesce
    theme_file: themes/matrix-green.yml
    cli_settled_color: "#b6ffd0"
    cli_gradient_start: "#004d26"
    cli_gradient_end: "#eafff2"
    duration_ms: 900
    frames: 20

CLI inline animation + charactor fade

  - name: neofetch-fade
    match:
      command: neofetch
    backend: cli
    features:
      - inline_animation
    animation_color_fade: true
    animation_color_darken_factor: 0.02
    live_render_duration_ms: 120
    live_render_mouse_quiet_ms: 280
    duration_ms: 900
    frames: 18

What `baeru` is for

Many terminal customization ideas fall into one of two extremes:

patch or fork the target application
build a brand-new terminal UI from scratch

baeru explores a third path: keep the original app, but wrap it with presentation and interaction layers.

That makes room for things like:

startup reveals that make htop and lazygit feel staged
theme-driven ANSI recoloring without patching the target app
highlight effects that blink and react to matching output
CLI animations that make plain command output settle into place
output transforms that mask or replace visible text while keeping the original command untouched

What it can do

TUI drama

reveal Captures the startup screen, animates it, then hands control back to the original TUI
live_color Rewrites ANSI colors live, including indexed palette replacement
keymap Applies per-command input remapping from YAML
live_render Rebuilds TUI state and animates dirty cells during updates

CLI drama

inline_animation Animates ordinary stdout with effects like coalesce, glitch, matrix, and sweep
highlight Watches for matching text and reacts with styled emphasis, blinking, captures, and hooks
replace / mask Rewrites only the visible output layer, useful for demos and screenshots

Quick start

The fastest way to get the vibe:

cargo run -- htop
cargo run -- lazygit
cargo run -- ls -la
cargo run -- -b cli -e '(?i)error|timeout' journalctl -n 50

More explicit examples:

cargo run -- -m reveal htop
cargo run -- -m color_live -t examples/themes/jirai-pink.yml htop
cargo run -- -m reveal -t examples/themes/jirai-pink.yml -k examples/keymaps/htop-vim.yml htop
cargo run -- -m live_render -t examples/themes/jirai-pink.yml htop
cargo run -- -b cli --effect matrix git status
cargo run -- -b cli -e '(?i)error' -e 'timeout' journalctl -n 50
cargo run -- -b cli -R '(?i)token=[A-Za-z0-9_]+' 'token=[redacted]' env

Installation

Release binaries

Prebuilt binaries are published on the GitHub Releases page.

Linux: x86_64-unknown-linux-gnu
macOS: aarch64-apple-darwin
Windows: x86_64-pc-windows-msvc

Download an archive from Releases, then place baeru somewhere on your PATH.

crates.io

If you already have a Rust toolchain installed, you can install from crates.io:

cargo install baeru

Build from source

git clone https://github.com/blacknon/baeru
cd baeru
cargo build --release
./target/release/baeru htop

Useful short options include -b for --backend, -m for --mode, -E for --effect, -c for --config-file, -t for --theme-file, and -k for --keymap-file.

If no --config-file is given, baeru looks for config files in this order:

./baeru.yml
$XDG_CONFIG_HOME/baeru/baeru.yml
~/.config/baeru/baeru.yml
~/.baeru.yml

For example:

cargo run -- htop
cargo run -- ls -la

You can also point to a config explicitly:

cargo run -- -c baeru.yml htop

If no command is specified and stdin is a terminal, htop is used as the default PoC target:

cargo run

Demo recipes

htop with reveal + recolor + keymap
lazygit with a faster startup reveal
journalctl with match-driven highlights
git status with animated settle effects
env or neofetch with visible masking for recordings and screenshots

Backends

`tui`

For interactive terminal applications such as htop or lazygit.

baeru -b tui htop
baeru -m reveal htop

`cli`

For ordinary commands such as ls, df, or git status.

baeru -b cli ls -la
baeru -b cli git status
printf 'hello\nworld\n' | baeru -b cli

`raw`

For plain passthrough behavior without added effects.

Features

Current matrix

Area	Name	Kind	Status	Notes
TUI	`reveal`	startup animation	stable PoC	startup capture + animated reveal
TUI	`live_color`	live color transform	stable PoC	ANSI SGR rewrite, supports palette replacement
TUI	`keymap`	input remap	stable PoC	YAML-driven byte-sequence remapping
TUI	`splash`	startup animation	stable PoC	simple pre-launch splash
TUI	`live_render`	live redraw animation	experimental	VT100 rebuild + changed-cell flash
CLI	`inline_animation` + `coalesce`	inline animation	stable PoC	noisy symbols converge into final text
CLI	`inline_animation` + `glitch`	inline animation	stable PoC	flickery noisy instability that settles quickly
CLI	`inline_animation` + `matrix`	inline animation	stable PoC	column-biased digital-rain style convergence
CLI	`inline_animation` + `scanline`	inline animation	stable PoC	moving scan band reveals text as it passes
CLI	`inline_animation` + `scatter`	inline animation	stable PoC	randomized positions settle into place across the screen
CLI	`inline_animation` + `sweep`	inline animation	stable PoC	left-to-right reveal
CLI	`inline_animation` + `wipe`	inline animation	stable PoC	diagonal wipe from sparse to full text
CLI	`inline_animation` + `fade`	inline animation	stable PoC	delayed text appearance
CLI	`inline_animation` + `plain`	passthrough-style	stable PoC	same backend path, no animation

`reveal`

Starts the target command in a PTY, captures the initial screen briefly, renders a startup animation, then switches to PTY passthrough.

baeru --mode reveal htop
baeru --mode reveal --capture-ms 420 --duration-ms 900 htop

Sample GIFs:

coalesce

sweep

fade

plain

`live_color`

Passes PTY output through while rewriting ANSI SGR colors.

baeru --mode color-live --theme-file examples/themes/jirai-pink.yml htop

Current approaches include:

gradient-based recoloring
indexed ANSI palette replacement via palette_map

`keymap`

Rewrites key input per command using YAML-defined mapping rules.

`inline_animation`

Animates CLI output inline below the prompt.

Without a theme or CLI color override: animates while preserving the original ANSI colors
With a theme or CLI color override: recolors output on the baeru side

Supported effects:

coalesce
glitch
matrix
scanline
scatter
sweep
wipe

Highlight rules

baeru can watch output for matching keywords or regular expressions and react to them. In CLI mode, matches are colorized and can trigger hooks or captures. In TUI rendering paths such as reveal and live_render, matches can also flash in place with side markers for a more aggressive alert feel.

CLI option:

baeru --backend cli -e '(?i)error' -e 'timeout' journalctl -n 50
baeru --backend cli -e '(?i)error' --highlight-capture-cli-text --highlight-command echo --highlight-command matched journalctl -n 50

-e, --highlight
- regex pattern, repeatable
--highlight-color
- default background color for CLI -e rules
- default is yellow: #ffff00
--highlight-command
- command argv for CLI-defined highlight rules
- repeat the option for each argv part
--highlight-capture-cli-text
- save full CLI text output when a CLI-defined highlight matches
--highlight-capture-tui-screenshot
- save a TUI SVG screenshot when a CLI-defined highlight matches
--highlight-output-dir
- output directory for CLI-defined highlight captures and manifests
--highlight-output-prefix
- filename prefix template for CLI-defined highlight captures and manifests
- supported tokens: {key}, {backend}, {capture_kind}, {ext}, {timestamp}, {env:NAME}
- rendered values are sanitized to safe filename characters

Config example:

profiles:
  - name: journal-alerts
    match:
      command: journalctl
    backend: cli
    features:
      - inline_animation
    highlight_color: "#ffff00"
    highlight_rules:
      - key: error
        pattern: "(?i)error|failed|panic"
        color: "#ffcc00"
        capture_cli_text: true
        output_dir: ./baeru-artifacts
        output_prefix: "alerts-{backend}-{env:USER}-"
        command: ["sh", "-c", "printf '%s\n' \"$BAERU_HIGHLIGHT_EVENT_JSON\""]

output_prefix is optional for both CLI flags and highlight_rules. When set, it is prepended to generated filenames inside output_dir.

Example:

baeru --backend cli \
  -e '(?i)error' \
  --highlight-capture-cli-text \
  --highlight-output-dir ./baeru-artifacts \
  --highlight-output-prefix 'nightly-{backend}-{timestamp}-' \
  journalctl -n 50

Per match rule, baeru can:

highlight matching text
run a command
write CLI output to a text file
write a TUI screen snapshot as SVG

Triggered commands receive context through environment variables:

BAERU_HIGHLIGHT_BACKEND
BAERU_HIGHLIGHT_KEY
BAERU_HIGHLIGHT_PATTERN
BAERU_HIGHLIGHT_MATCHES_JSON
BAERU_HIGHLIGHT_EVENT_JSON
BAERU_HIGHLIGHT_CAPTURE_PATH
BAERU_HIGHLIGHT_CAPTURE_KIND

Replace and mask rules

baeru can also rewrite visible output without changing the underlying application.

CLI options:

baeru -b cli -R '(?i)token=[A-Za-z0-9_]+' 'token=[redacted]' env
baeru -b cli -M '(?i)password=.*' sh -c 'printf "password=hunter2\n"'

-R, --replace <PATTERN> <TEXT>
- regex-based visible replacement
- repeatable
- replacement is width-preserving
- if replacement is shorter than the matched text, it is padded with spaces
- if replacement is longer, only the leading characters are used
-M, --mask <PATTERN>
- regex-based masking
- repeatable
--mask-char
- masking character
- default is *

Config example:

profiles:
  - name: fetch-safe
    match:
      command: neofetch
    backend: cli
    features:
      - inline_animation
    replace_rules:
      - pattern: "Debian GNU/Linux"
        replacement: "Distro"
    mask_rules:
      - pattern: "(?i)kernel: .*"
        mask_char: "#"

These transforms are applied to CLI output and to TUI rendering paths such as reveal and live_render.

baeru --backend cli --effect coalesce ls -la
baeru --backend cli --effect sweep git status

Sample GIFs:

coalesce

sweep

fade

`live_render` experimental

Rebuilds the target TUI screen from VT100 state, redraws it from baeru, and animates changed cells during live updates.

baeru --mode live_render --theme-file examples/themes/jirai-pink.yml htop

This mode is still intentionally experimental, but it is no longer just a full-screen redraw toy. Current improvements include:

row-diff and dirty-row redraw instead of blind full-screen repaint
simple scroll hints for vertical updates
cursor visibility / cursor position restoration
PTY resize propagation and parser recreation on terminal resize
mouse / cursor-mode / bracketed-paste passthrough for better input fidelity
short live update animation with coalesce / glitch / matrix / scanline / scatter / sweep / wipe / fade / plain

Recommended profile-style tuning:

profiles:
  - name: htop-live-render-experimental
    match:
      command: htop-live
    backend: tui
    features:
      - live_render
      - keymap
    effect: coalesce
    keymap_file: examples/keymaps/htop-vim.yml
    live_render_duration_ms: 90
    live_render_mouse_quiet_ms: 180
    animation_color_fade: true
    animation_color_darken_factor: 0.22

live_render_duration_ms controls the short redraw animation window. live_render_mouse_quiet_ms controls how long baeru stays in quieter redraw mode after wheel / drag / up-down style input. animation_color_fade darkens characters before they settle to their target colors during reveal and live_render.

Configuration

`baeru.yml`

baeru resolves behavior from profiles matched against:

executable basename
exact executable path
optional args_prefix

Example:

profiles:
  - name: htop-jirai-vim
    match:
      command: htop
    backend: tui
    features:
      - reveal
      - live_color
      - keymap
    # omit `effect` to use the default TUI fade
    animation_color_fade: true
    animation_color_darken_factor: 0.22
    keymap_file: examples/keymaps/htop-vim.yml
    theme_file: examples/themes/jirai-pink.yml
    capture_ms: 360
    duration_ms: 720
    frames: 24

  - name: ls-inline
    match:
      command: ls
    backend: cli
    features:
      - inline_animation
    effect: coalesce
    theme_file: themes/matrix-green.yml

  - name: htop-live-render-experimental
    match:
      command: htop-live
    backend: tui
    features:
      - live_render
      - keymap
    effect: coalesce
    keymap_file: examples/keymaps/htop-vim.yml
    live_render_duration_ms: 90
    live_render_mouse_quiet_ms: 180
    animation_color_fade: true
    animation_color_darken_factor: 0.22

Theme YAML

Themes support the original gradient-based recoloring style:

name: jirai-pink
default_fg: "#ffcdeb"
default_bg: "#120018"
force_default: true
foreground:
  - { at: 0.00, color: "#84205c" }
  - { at: 0.30, color: "#ff45ac" }
  - { at: 0.62, color: "#ff8fd6" }
  - { at: 0.84, color: "#ffcdeb" }
  - { at: 1.00, color: "#fff2fa" }
background:
  - { at: 0.00, color: "#120018" }
  - { at: 0.55, color: "#570a41" }
  - { at: 1.00, color: "#ff8fcf" }

They also support indexed ANSI palette replacement:

name: gundam-tricolor-htop
default_fg: "#f3f6ff"
default_bg: "#08111f"
force_default: true
palette_map:
  1: "#ff5a5f"
  3: "#ffd84a"
  4: "#3f7dff"
  15: "#ffffff"
background_palette_map:
  4: "#0f214a"

This is especially useful for htop-style TUIs where preserving rough semantic color roles matters more than pure luminance mapping.

Keymap YAML

keymap:
  j: down
  k: up
  h: left
  l: right
  ctrl-d: page-down
  ctrl-u: page-up
  r: f5
  "/": f3

Supported key names include:

arrows: up, down, left, right
navigation: home, end, page-up, page-down
function keys: f1 ... f10
control keys: ctrl-a ... ctrl-z
special keys: enter, esc, tab, backspace
printable single characters such as j, k, /

Themes

There are two theme buckets right now:

themes/ More baseline examples
examples/themes/ More expressive or experimental sample themes

Current example themes include:

jirai-pink
eva-unit-01
eva-unit-01-htop
gundam-tricolor-htop

Keymaps

Example keymap files live under:

examples/keymaps/

Limitations

This is still a PoC. Terminal restoration and signal handling can be hardened further.
reveal captures a single approximate startup screen. Very unstable startup screens may need capture_ms tuning.
live_render is experimental. It is more usable now, but complex TUIs may still flicker, briefly desynchronize, or lose some emulator-specific behavior.
CLI inline animation is still less robust than plain passthrough for some terminals and very large outputs.
Key remapping is byte-sequence based. Complex keyboard protocols and emulator-reserved shortcuts still need more careful handling.
Mouse mapping is not implemented yet, though the architecture leaves room for a future mousemap layer.
Command-specific semantic adapters are still future work.

License

MIT. See LICENSE.

ASW-G-01?

? "Here stands the truth of Gjallarhorn. All of you... gather beneath Bael!"

? "It's Bael!"

? "The soul of Agnika Kaieru!"

? "That's the other Bael, it is Baeru"

Name		Name	Last commit message	Last commit date
Latest commit History 46 Commits
.github/workflows		.github/workflows
assets		assets
examples		examples
src		src
themes		themes
.dockerignore		.dockerignore
.gitignore		.gitignore
Cargo.lock		Cargo.lock
Cargo.toml		Cargo.toml
Dockerfile		Dockerfile
LICENSE		LICENSE
README.md		README.md
baeru.yml		baeru.yml
docker-compose.yml		docker-compose.yml
mise.toml		mise.toml

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baeru

About

Releated project

First look

TUI reveal + live color

TUI reveal + live color + live rendor + realtime masking + highligh text + charactor fade

CLI inline animation + theme

CLI inline animation + charactor fade

What baeru is for

What it can do

TUI drama

CLI drama

Quick start

Installation

Release binaries

crates.io

Build from source

Demo recipes

Backends

tui

cli

raw

Features

Current matrix

reveal

live_color

keymap

inline_animation

Highlight rules

Replace and mask rules

live_render experimental

Configuration

baeru.yml

Theme YAML

Keymap YAML

Themes

Keymaps

Limitations

License

ASW-G-01?

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Releases 3

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What `baeru` is for

`tui`

`cli`

`raw`

`reveal`

`live_color`

`keymap`

`inline_animation`

`live_render` experimental

`baeru.yml`

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