mtr braille graph

bartman
2025-06-23

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I often monitor network stability with mtr, which can show a time series of how the network is doing at different hops between two endpoints. I recently made an improvement to mtr that shows the time series as a graph using braille characters.

braille #

The Unicode character set has many glyphs, including many block drawing characters. Within those there are two types of braille pattern blocks: 6-dots and 8-dots, the latter of which has a 4x2 matrix of dots ⣿, giving us 256 combinations of dots.

I had played with braille characters before in my blot plotting library. I had more leeway there, since the canvas was limited by the size of the terminal. This time I only have one line of text.

graphing #

If you’re not familiar, mtr has multiple modes, including “display mode 2”, which already displays a series of color codes alphanumeric characters to indicate the round trip time to the hop along the routed being traced. It looks like this…

1❯ mtr -t 8.8.8.8 --displaymode=2

Adding braille characters has two major wins for mtr display:

twice the history on the horizontal dimension
can show relative latency in vertical dimension

1❯ mtr -t 8.8.8.8 --displaymode=3

running #

This change has been merged (422f4a0) into mtr, but I don’t think it’s part of any OS release. So you can build it yourself…

using docker

First, grab this Dockerfile, and optionally edit if.

Then from the directory containing the Dockerfile, run…
```
1❯ docker build -t mtr-build .
2❯ docker run -it mtr-build /mtr/mtr -t 8.8.8.8 --display=3
```

manual (Debian)

1❯ sudo apt update
2❯ sudo apt install git build-essential autoconf automake libncurses-dev libjansson-dev libcap-dev pkg-config locales
3❯ git clone
4❯ git clone https://github.com/traviscross/mtr.git /mtr
5❯ ./bootstrap.sh
6❯ ./configure
7❯ make
8❯ ./mtr -t 8.8.8.8 --display=3

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