Convert a ruby ​script to a bash script

I need to turn this ruby ​​script into bash for i3 on Ubuntu:

#!/usr/bin/env ruby

sink =  %x`pacmd list-sinks | grep -e 'name:' -e 'index:' -e 'active'`

er = /\* index: ([0-9])/

er.match sink

if $1 == "1"
    print 'usb'
else 
    print 'mic'
end

The script must be used for i3block and displayed on i3bar. As an example the following script shows the result on i3block, but I don't understand how it does it.

#!/bin/bash

BAT=$(acpi -b | grep -E -o '[0-9][0-9]?%')

echo "BAT: $BAT"

exit 0

Thanks for your help!

#!/bin/bash
sink=$(pacmd list-sinks | grep '* index:')
if [[ "${sink:11:11}" -eq "1" ]]
then
    echo 'usb'
else
    echo 'mic'
fi

This is making a lot of assumptions, as you did not explain much about the ruby script you pasted and what the actual objective is.

This bash script does a grep on the output of the pulseaudo list of sinks, where the index is preceded with a *. then from this line, the 11th character is checked. If it is a 1 then echo out USB, otherwise MIC.

As said, this is presuming a lot and this style of programming can go hilariously wrong if there are other indexes in play, or you do want the name of the device...

I don't know i3bar or i3blocks, but it maybe that you need to set an interval in i3blocks or wrap the script in a while loop, because a script runs, outputs something and then exit's, so something should continuously trigger it. The way you do it is i3 specific, which I know nothing about. Based on the man pages, this is what I would try first

[pulse]
command=/usr/local/bin/check_pulse.sh
interval=15

http://manpages.ubuntu.com/manpages/bionic/man1/i3blocks.1.html