iq-scm / fcat

A 3x faster implementation of cat, using splice

😼 fcat

fcat, short for fastcat, is a cat implementation in Rust using Linux's splice syscall.
With that little trick, it's more than three times as fast as the system cat in our benchmarks.
Read the announcement here.

⚠️ This project is currently broken on newer Linux versions (5.9+) because of some changes
concerning the splice system call. (See here and here.) This can't be fixed unless changes to the kernel get made.

Performance

cat myfile | pv -r > /dev/null
[1.90GiB/s]

fcat myfile | pv -r > /dev/null
[5.90GiB/s]

Installation

Note: Only works on Linux.
(But you can send me a pull request for other operating systems.)

cargo install fcat

Usage

fcat file1 file2 file3

Project goals

• Be the fastest cat in town.
• Be a drop-in replacement for (POSIX) cat.

Non-goals

• Provide any additional functionality other than what cat provides.
  If you're looking for a more beautiful cat, check out bat.

Known issues

If you run fcat /dev/zero >> myfile, it will fail with exit code EINVAL because, according to the splice manpage: "The target file is opened in append mode."

Trivia

• You probably won't ever need this, but it's a fun little experiment.
  Still, I wonder why this is not part of e.g. GNU cat...
• What I like the most about the project is the logo.

License

fcat is licensed under either of

• Apache License, Version 2.0, (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.