neo-lolcat

Rust reimplementation of lolcat maintained by skyline69. It sticks to the standard library while matching the original help surface.

Features

• Streams stdin or multiple files (treating - as stdin) with the familiar rainbow gradient.
• Supports the classic flags (--spread, --freq, --seed, --animate, etc.) plus a --debug mode for diagnostics.
• Detects truecolor terminals automatically while allowing explicit --truecolor/--force overrides.
• Handles Broken pipe/SIGPIPE situations gracefully so pipelines like macchina | lolcat -t --animate 1 | head -n1 exit cleanly.
• Includes unit and integration tests to lock in parser behavior and CLI regressions.

Installing

Install with the following command:

cargo install neo-lolcat

Building

cargo build --release

Optimized binaries are emitted to target/release/lolcat. The release profile enables opt-level=3, fat LTO, single codegen unit, and panic = "abort" for maximum throughput.

Testing

cargo fmt
cargo test
cargo clippy -- -D warnings

The integration suite under tests/cli.rs spawns the compiled binary and checks help/version output plus forced-color pipelines; tests/stress.rs feeds random binary data to guard against crashes. For longer runs, scripts/stress.sh streams configurable amounts of random data through the release binary (requires Python 3).

Continuous Integration

A GitHub Actions workflow (.github/workflows/ci.yml) runs fmt, clippy, unit + integration tests, and a release build on every push/PR to keep the binary stable across toolchains.

Usage

Usage: lolcat [OPTION]... [FILE]...

Concatenate FILE(s), or standard input, to standard output.
With no FILE, or when FILE is -, read standard input.

Refer to lolcat --help for the complete flag list and examples. Use --debug or the legacy LOLCAT_DEBUG=1 environment variable to see internal diagnostics when troubleshooting terminal quirks.