added -0 paramter for better compability with xargs

main.go

@@ -14,7 +14,7 @@ import (
 	"git.milar.in/milarin/buildinfo"
 )
 
-var (
+var ( //flags
 	// regex with sub groups
 	input = flag.String("i", `^(.|\n)*?$`, "input pattern")
 
@@ -49,6 +49,12 @@ var (
 
 	showVersion = flag.Bool("v", false, "show version and exit")
 
+	OutputNullByte = flag.Bool("0", false, "use nullbyte instead of newline as line separator for printing output")
+)
+
+var ( // globals
+	LineSeparator string = "\n"
+
 	replacePattern     = regexp.MustCompile(`\{(\d+)(?::(.*?))?(?::(.*?))?(?::(.*?))?\}`)
 	numMutationPattern = regexp.MustCompile(`([+\-*/])(\d+|\((\d+)\))`)
 )
@@ -61,6 +67,10 @@ func main() {
 		return
 	}
 
+	if *OutputNullByte {
+		LineSeparator = string(rune(0))
+	}
+
 	pattern, err := regexp.Compile(*input)
 	if err != nil {
 		panic(err)
@@ -73,12 +83,12 @@ func main() {
 
 		if len(matches) == 0 {
 			if *keepUnmatched {
-				fmt.Println(line)
+				fmt.Print(line, LineSeparator)
 			}
 			continue
 		}
 
-		fmt.Println(replaceVars(escapedOutput, matches...))
+		fmt.Print(replaceVars(escapedOutput, matches...), LineSeparator)
 	}
 }
 
@@ -87,13 +97,31 @@ func readLines(r io.Reader) <-chan string {
 
 	go func(out chan<- string, source io.Reader) {
 		defer close(out)
-
 		r := bufio.NewReader(source)
 
 		for {
+			line, err := ReadLine(r)
+
+			// use data as line if reading was successfull or EOF has been reached
+			// in the latter case: only use data if something could be read until EOF
+			if err == nil || err == io.EOF && line != "" {
+				out <- line
+			}
+
+			if err != nil {
+				return
+			}
+		}
+	}(ch, r)
+
+	return ch
+}
+
+func ReadLine(r *bufio.Reader) (string, error) {
+	lines := make([]string, 0, *lineParseAmount)
+
 	var line string
 	var err error
-			lines := make([]string, 0, *lineParseAmount)
 	for line, err = r.ReadString('\n'); ; line, err = r.ReadString('\n') {
 		if rn, size := utf8.DecodeLastRuneInString(line); rn == '\n' {
 			line = line[:len(line)-size]
@@ -108,20 +136,7 @@ func readLines(r io.Reader) <-chan string {
 	}
 
 	linesCombined := strings.Join(lines, "\n")
-
+	return linesCombined, err
-			// use data as line if reading was successfull or EOF has been reached
-			// in the latter case: only use data if something could be read until EOF
-			if err == nil || err == io.EOF && linesCombined != "" {
-				out <- linesCombined
-			}
-
-			if err != nil {
-				return
-			}
-		}
-	}(ch, r)
-
-	return ch
 }
 
 func replaceVars(format string, vars ...string) string {