---
title: "lolcat-c"
external_links:
    - name: Sources
      url: "https://git.jaseg.de/lolcat.git"
    - name: Github
      url: "https://github.com/jaseg/lolcat"
    - name: Issues
      url: "https://github.com/jaseg/lolcat/issues"
summary: >
    lolcat-c is a small, high-performance re-implementation of the
    `lolcat <https://github.com/busyloop/lolcat>`__
    rainbow cat utility. lolcat-c is meant as a lolcat that you can actually use in production. It is fast, not slowing
    down whatever you pipe through it, and it robustly handles real-world terminal output including escape sequences.
---

What?
=====

.. image:: LOLCat-Rainbow.jpg

Screenshot
==========

.. image:: screenshot.png

.. image:: sl.gif

Installation
============

Archlinux
---------

There's an `AUR package <https://aur.archlinux.org/packages/c-lolcat>`__:

.. code:: sh

    $ git clone https://aur.archlinux.org/packages/c-lolcat
    $ cd c-lolcat
    $ makepkg -csi

Fedora
------

.. code:: sh

    $ dnf install lolcat

Ubuntu (Snap)
-------------

See `this awesome blog post by a kind person from the internet <https://blog.simos.info/how-to-make-a-snap-package-for-lolcat-with-snapcraft-on-ubuntu/>`__:

.. code:: sh

    $ snap install lolcat-c

Mac
---

Build loclcat with:

.. code:: sh

    $ make lolcat

...and put the resulting binary at a place of your choice.

Others
------

.. code:: sh

    $ make && sudo make install

Why?
====

This `lolcat` clone is an attempt to reduce the world's carbon dioxide emissions by optimizing inefficient code. It's
>10x as fast and <0.1% as large as the original one.

.. code:: sh

    newton~/d/lolcat <3 dmesg>foo
    newton~/d/lolcat <3 time upstream/bin/lolcat foo
    13.51user 1.34system 0:15.99elapsed 92%CPU (0avgtext+0avgdata 10864maxresident)k
    0inputs+0outputs (0major+1716minor)pagefaults 0swaps
    newton~/d/lolcat <3 time ./lolcat foo
    0.02user 0.00system 0:00.09elapsed 34%CPU (0avgtext+0avgdata 1936maxresident)k
    0inputs+0outputs (0major+117minor)pagefaults 0swaps

Bonus comparison with `python-lolcat <https://github.com/tehmaze/lolcat/>`__:

.. code:: sh

    newton~/d/lolcat <3 dmesg>foo
    $ time python-lolcat foo
    12.27user 0.00system 0:12.29elapsed 99%CPU (0avgtext+0avgdata 11484maxresident)k
    0inputs+0outputs (0major+1627minor)pagefaults 0swaps
    $ time c-lolcat foo
    0.29user 0.00system 0:00.30elapsed 98%CPU (0avgtext+0avgdata 468maxresident)k
    0inputs+0outputs (0major+21minor)pagefaults 0swaps

(Read: `c-lolcat << python-lolcat << ruby-lolcat`)