added lineParseAmount parameter

main.go

@@ -4,6 +4,7 @@ import (
 	"bufio"
 	"flag"
 	"fmt"
+	"io"
 	"os"
 	"regexp"
 	"strconv"
@@ -25,6 +26,11 @@ var (
 	// they will be copied without any changes
 	keepUnmatched = flag.Bool("k", false, "keep unmatched lines")
 
+	// if the amount of lines in stdin are not divisible by lineParseAmount,
+	// the last lines will be ignored completely.
+	// it may be useful to have a boolean flag for this behavior
+	lineParseAmount = flag.Int("n", 1, "amount of lines to feed into input pattern")
+
 	replacePattern = regexp.MustCompile(`\{(\d+)(?::(.*?))?\}`)
 )
 
@@ -36,8 +42,7 @@ func main() {
 		panic(err)
 	}
 
-	r := bufio.NewReader(os.Stdin)
-	for line, err := r.ReadString('\n'); err == nil; line, err = r.ReadString('\n') {
+	for line := range readLines(os.Stdin) {
 		line = line[:len(line)-1]
 		matches := pattern.FindStringSubmatch(line)
 
@@ -52,6 +57,34 @@ func main() {
 	}
 }
 
+func readLines(r io.Reader) <-chan string {
+	ch := make(chan string, 10)
+
+	go func(out chan<- string, source io.Reader) {
+		defer close(out)
+
+		r := bufio.NewReader(source)
+
+		for {
+			var line string
+			var err error
+			lines := make([]string, 0, *lineParseAmount)
+			for line, err = r.ReadString('\n'); err == nil; line, err = r.ReadString('\n') {
+				lines = append(lines, line)
+				if len(lines) == cap(lines) {
+					break
+				}
+			}
+			if err != nil {
+				return
+			}
+			out <- strings.Join(lines, "")
+		}
+	}(ch, r)
+
+	return ch
+}
+
 func replaceVars(format string, vars ...string) string {
 	replacements := replacePattern.FindAllStringSubmatch(format, -1)