checksum colorizer

checksum-colorizer.go

package main

import (
	"bufio"
	"fmt"
	"os"
	"log"
	"regexp"
)

func repl1(hex []byte) []byte {
	return []byte(fmt.Sprintf("\x1B[38;5;%dm%c%c\x1B[0m", hex[0] + 0x10*hex[1], hex[0], hex[1]))
}

func repl(line []byte) []byte {
	hexet, _ := regexp.Compile("[0-9a-fA-F][0-9a-fA-F]")
	return hexet.ReplaceAllFunc(line, repl1)
}

func main() {
	hexets, _ := regexp.Compile("([^0-9a-zA-Z]|^|0x)([0-9a-fA-F][0-9a-fA-F])+([^0-9a-zA-Z]|$)")
	
	scanner := bufio.NewScanner(os.Stdin)
	for scanner.Scan() {
		line := scanner.Bytes()
		line = hexets.ReplaceAllFunc(line, repl)
		fmt.Println(string(line))
	}
	
	if err := scanner.Err(); err != nil {
		log.Println(err)
	}
}

go build then ; sha256sum * | ./foo. colors the hashes for easy comparison.