Kestrel

Interactive regex filter and text file viewer designed for log files.

Features

• Live regex filter (Hyperscan/Vectorscan) with PCRE2 capture-group highlighting
• Match counter (X of Y), next/prev match (n / Shift+N)
• Filter view: show only matched lines
• Time-range filter for leading ISO-8601 timestamps (including UTC offsets)
• Log-level auto-tint (ERROR / WARN / INFO / DEBUG)
• Synthetic minimap with click-to-jump and viewport indicator
• Light/dark theme; configurable match/cursor colors
• Line-range selection: click + Shift+click (or Shift+arrows / PgUp / PgDn) → Ctrl+C to copy
• Go-to-line (Ctrl+G), copy/paste search pattern (Ctrl+C / Ctrl+V)
• Recent-files list, drag-and-drop file open

In-app help: Help → Keyboard Shortcuts.

System dependencies

Debian / Ubuntu / Mint:

sudo apt update
sudo apt install -y build-essential cmake pkg-config ragel libboost-dev libsqlite3-dev libgl1-mesa-dev libx11-dev libxrandr-dev libxinerama-dev libxcursor-dev libxi-dev

Submodules

git submodule update --init --recursive

Third-party sources live under third_party/:

• imgui/ — ocornut/imgui
• ImGuiFileDialog/ — aiekick/ImGuiFileDialog
• glfw/ — glfw/glfw
• vectorscan/ — VectorCamp/vectorscan
• pcre2/ — PCRE2Project/pcre2
• doctest/ — doctest/doctest (vendored header)

Build

cmake -S . -B build -DCMAKE_BUILD_TYPE=Release
cmake --build build -j4

The first configure downloads spdlog and JetBrains Mono. To install outside the source checkout (including the icon and font assets):

cmake --install build

Run

./build/kestrel

Test

ctest --test-dir build --output-on-failure

For an AddressSanitizer build, configure with -DKESTREL_ENABLE_ASAN=ON.

Releases

Pushing a semantic-version tag (for example, v1.2.3) builds, tests, and publishes Linux and Apple Silicon macOS release archives. Each archive contains the files that belong under /usr/local, including the executable, font, and icon assets.

git tag v1.2.3
git push origin v1.2.3

To install a downloaded release archive:

tar -xzf kestrel-<platform>-<version>.tar.gz -C /tmp/kestrel
sudo cp -a /tmp/kestrel/. /usr/local/
kestrel

Bug reports

Logs go to stderr. Capture with debug verbosity and attach to the issue:

KESTREL_LOG=debug ./build/kestrel 2> kestrel.log

Valid KESTREL_LOG values: trace, debug, info, warn (default), err, off.

Icon Credit (modified by me)

American kestrel bird icons created by Delwar018 - Flaticon