Add a linux waybar battery module.

ansible/roles/sway/files/waybar_battery_linux

@@ -0,0 +1,62 @@
+#!/usr/bin/env bash
+#
+# Read battery status in FreeBSD
+set -euo pipefail
+IFS=$'\n\t'
+DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+
+SLEEP_INTERVAL=${SLEEP_INTERVAL:-30}
+
+batteries=$(find /sys/class/power_supply -name 'BAT*')
+
+while true; do
+    text=""
+    tooltip=""
+    percentage=""
+    while read bat; do
+        battery_now=$(cat "$bat/charge_now")
+        battery_capacity=$(cat "$bat/charge_full")
+        battery_percentage=$(( battery_now * 100 / battery_capacity ))
+        battery_status=$(cat "$bat/status")
+        seconds_remaining="-1"
+
+        if [ $battery_status = "Charging" ]; then
+            if [ $battery_percentage -eq 100 ]; then
+                battery_icon=""
+            else
+                battery_icon=""
+            fi
+        elif [ $battery_percentage -le 20 ]; then
+            battery_icon=""
+        elif [ $battery_percentage -le 40 ]; then
+            battery_icon=""
+        elif [ $battery_percentage -le 60 ]; then
+            battery_icon=""
+        elif [ $battery_percentage -le 80 ]; then
+            battery_icon=""
+        elif [ $battery_percentage -lt 100 ]; then
+            battery_icon=""
+        else
+            battery_icon=""
+        fi
+        if [ $seconds_remaining -eq -1 ]; then
+            time_remaining="unknown time remaining."
+        else
+            time_remaining=$(printf '%dh:%dm:%ds\n' $((seconds_remaining/3600)) $((seconds_remaining%3600/60)) $((seconds_remaining%60)) )
+        fi
+
+        text="$text${battery_percentage}% ${battery_icon}"
+        tooltip="$tooltip${time_remaining}"
+        percentage="$percentage${battery_percentage}"
+    done<<<"$batteries"
+
+
+    jq --unbuffered --compact-output <<EOF
+{
+"text":"$text",
+"tooltip":"$tooltip",
+"percentage":$percentage
+}
+EOF
+    sleep $SLEEP_INTERVAL
+done