barrette (brt)

barrette is a user-friendly wrapper for wob / xob / overlay bars reading percentages from STDIN. It provides the brt command.

I created it because I found these tools nice, but a bit cumbersome to use. The idea is simple:

1. Run a pre-defined command, such as brt volume_up

2. Get a nice overlay bar showing a percentage returned by the command

Installation

From a pre-built executable

Grab a release from the releases page.

From source (requires a recent rust version to be installed)

cargo install --branch main --git https://github.com/lukapeschke/barrette

Usage

For a complete CLI reference, run brt --help

The first step is to create config file. See example-wob.toml to get an example. I use this file with wob on sway on Fedora 33.

Configuration

The config is written in TOML. By default, brt will expect to find it in ~/.config/barrette/barrette.toml, but another path can specified through the -c/--config CLI flag.

It is composed of a process and an array of commands:

[process]
# required, name of the command to use
command = "wob"
# optional, array of arguments to pass to the command
args = []
# optional, path of the FIFO to create that will be used as the command's STDIN. Defaults to "/tmp/barrette_fifo"
fifo_path = "/tmp/barrette_fifo"
# optional, permissions of the FIFO in octal notation (prefixed with 0o)
fifo_mode = 0o600

[[commands]]
# required, name that will be passed to brt when running "brt COMMAND"
name = "volume_up"
# required, name of the command to use
command = "amixer"
# optional, array of arguments to pass to the command
args = ["sset", "Master", "5%+"]
# optional, regex that should be used to extract the percentage from the command's output. Defaults to "([0-9]+)%".
# The regex is compiled and matched using rust's regex library. It must include one unnamed capture group. Percentage
# symbols ('%') will be removed.
regex = "([0-9]+)%"

[[commands]]
name = "other_command"
command = "..."

Additional commands can be added in new [[commands]] sections.

How it works

Admitting that we've run brt volume_up with the config above:

1. First, brt checks if the process is already running. If it is, it directly skips to step 4.
2. If not, it checks if the FIFO described in the config exists, and creates if if needed.
3. The process is started.
4. The command matching "volume_up" is run
5. The command's output is parsed and the percentage is extracted
6. The extracted percentage is written to the previously created FIFO, followed by a carriage return (\n)