The splice family of Linux system calls can transfer data between file descriptors without the need to copy data into userspace. Instead of a userspace buffer, they rely on an ordinary Unix pipe as a kernel-level buffer. The `splice' and `tee' syscalls are also provided by the {sleepy_penguin}[https://yhbt.net/sleepy_penguin/] library. "io_splice" remains maintained for old applications or users experimenting with the vmsplice syscalls