init: create bat

.gitignore

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+bat
+
+# Binaries for programs and plugins
+*.exe
+*.exe~
+*.dll
+*.so
+*.dylib
+
+# Test binary, built with `go test -c`
+*.test
+
+# Output of the go coverage tool, specifically when used with LiteIDE
+*.out
+
+# Dependency directories (remove the comment below to include it)
+# vendor/

LICENSE

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+MIT License
+
+Copyright (c) 2021 Tshaka Eric Lekholoane
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

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+# `bat`
+
+```
+                                      bat
+									  
+NAME
+	bat - battery management utility for Linux laptops
+
+SYNOPSIS
+	bat [OPTION]
+	
+DESCRIPTION
+    -c, --capacity,     print current battery level
+    -h, --help,         print this help document
+    -t, --threshold,    print the current charging threshold limit
+                        append a value between 1 and 100 to set a new threshold
+    -s, --status        print charging status
+```
+
+## About
+
+Aims to replicate the functionality of the [ASUS Battery Health Charging](https://www.asus.com/us/support/FAQ/1032726/) utility for ASUS laptops on Windows which aims to prolong the battery's life-span <a href="https://electrek.co/2017/09/01/tesla-battery-expert-recommends-daily-battery-pack-charging/"><sup>1</sup></a> <a href="https://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries"><sup>2</sup></a>.
+
+## Installation
+
+Precompiled binaries (Linux x86-64) are available from the [GitHub releases page](https://github.com/leveson/bat/releases).
+
+Alternatively, one could build the binary oneself by running the following [Go](https://golang.org/) command,
+```shell
+$ go build bat.go
+```
+and placing the resulting binary in a directory that is in their `$PATH` such as `/usr/local/bin`.

bat.go

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+package main
+
+import (
+	"errors"
+	"fmt"
+	"log"
+	"os"
+	"os/exec"
+	"strconv"
+	"strings"
+)
+
+var help string = `
+                                      bat
+									  
+NAME
+	bat - battery management utility for Linux laptops 
+
+SYNOPSIS
+	bat [OPTION]
+	
+DESCRIPTION
+    -c, --capacity,     print current battery level
+    -h, --help,         print this help document
+    -t, --threshold,    print the current charging threshold limit
+                        append a value between 1 and 100 to set a new threshold
+    -s, --status        print charging status
+
+REFERENCE
+	https://wiki.archlinux.org/index.php/Laptop/ASUS#Battery_charge_threshold
+
+                                13 JANUARY 2021
+`
+
+func cat(file string) {
+	cmd := exec.Command("cat", file)
+	out, err := cmd.Output()
+	if err != nil {
+		log.Fatal(err)
+	}
+	fmt.Print(string(out))
+}
+
+func page(out string) {
+	cmd := exec.Command("/usr/bin/less")
+	cmd.Stdin = strings.NewReader(out)
+	cmd.Stdout = os.Stdout
+	err := cmd.Run()
+	if err != nil {
+		log.Fatal(err)
+	}
+}
+
+func setThreshold(t int) {
+	st := fmt.Sprintf("echo %d > "+
+		"/sys/class/power_supply/BAT0/charge_control_end_threshold", t)
+	cmd := exec.Command("su", "-c", st)
+	fmt.Print("Root password: ")
+	cmd.Stdin = os.Stdin
+	err := cmd.Run()
+	fmt.Println()
+	if err != nil {
+		fmt.Println("Authentication failure.")
+		os.Exit(1)
+	}
+}
+
+func main() {
+	nArgs := len(os.Args)
+
+	if nArgs == 1 {
+		page(help)
+		os.Exit(1)
+	}
+
+	switch os.Args[1] {
+	case "-c", "--capacity":
+		cat("/sys/class/power_supply/BAT0/capacity")
+	case "-h", "--help":
+		page(help)
+	case "-t", "--threshold":
+		switch {
+		case nArgs > 3:
+			fmt.Print("Expects single argument.\n")
+		case nArgs == 3:
+			t, err := strconv.Atoi(os.Args[2])
+			if err != nil {
+				if errors.Is(err, strconv.ErrSyntax) {
+					fmt.Print("Argument should be an integer.\n")
+					os.Exit(1)
+				} else {
+					log.Fatal(err)
+				}
+			}
+			if t < 1 || t > 100 {
+				fmt.Print("Number should be between 1 and 100.\n")
+				os.Exit(1)
+			}
+			setThreshold(t)
+			fmt.Printf("Charging threshold set to %s.\n", os.Args[2])
+		default:
+			cat("/sys/class/power_supply/BAT0/charge_control_end_threshold")
+			os.Exit(0)
+		}
+	case "-s", "--status":
+		cat("/sys/class/power_supply/BAT0/status")
+	default:
+		fmt.Printf("There is no %s option. Use bat --help to see a list of"+
+			"available options.\n", os.Args[1])
+	}
+}