fsrx
the rest of the line the page cornea iris lens retina fovea optic nerve
Fig. 1. The fovea, where sight is sharpest, spans about 6 to 8 letters at reading distance (Rayner, 1998).

Flow state reading in the terminal

fsrx dims the end of each word.

Give it a file or pipe text in. It prints each word with the first part at full strength and the rest dimmed. Add -c and the first part is bold.

$ echo "Call me Ishmael." | fsrx
brew install jrnxf/tap/fsrx

Try it

Fixation, -f Saccade, -s Contrast, -c

$ fsrx

Scrolling

The text from Try it, scrolling past a fixed line. In a terminal you scroll it yourself with fsrx notes.txt | less -R.

Speed Text

How it works

Options

Reads a file, or standard input.

-f l|m|h
bright part of each word: 30, 50 or 70%. Default m.
-s l|m|h
bright start on every 3rd, 2nd or every word. Default h.
-c
bold the bright part.
[PATH]
file to read; stdin if left out.

Install

brew install jrnxf/tap/fsrx
cargo install fsrx

Also in the AUR and NetBSD (textproc/fsrx).

Reading speed

Studies found no reading-speed gain (Snell, 2024). It does shift where the eye first lands in long words (Parker et al., 2026).

Credit

Inspired by, but not affiliated with, Renato Casutt's Bionic Reading.