diff --git a/.gitignore b/.gitignore
index 739a66d..c7715b4 100644
--- a/.gitignore
+++ b/.gitignore
@@ -12,3 +12,4 @@ vendor
 /obipairing
 /obipcr
 /obifind
+/obidistribute
diff --git a/pkg/obiformats/dispatcher.go b/pkg/obiformats/dispatcher.go
index a47d4ee..1ebd038 100644
--- a/pkg/obiformats/dispatcher.go
+++ b/pkg/obiformats/dispatcher.go
@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"log"
 	"sync"
+	"sync/atomic"
 
 	"git.metabarcoding.org/lecasofts/go/obitools/pkg/obiseq"
 )
@@ -21,26 +22,25 @@ func WriterDispatcher(prototypename string,
 	jobDone.Add(1)
 
 	go func() {
-		n := 0
+		n := int32(0)
 		for newflux := range dispatcher.News() {
-			data, _ := dispatcher.Outputs(newflux)
-			out, err := formater(data,
-				fmt.Sprintf(prototypename, newflux),
-				options...)
-			if err != nil {
-				log.Fatalf("cannot open the output file for key %s", newflux)
-			}
+			go func(newflux string) {
+				data, _ := dispatcher.Outputs(newflux)
+				out, err := formater(data,
+					fmt.Sprintf(prototypename, newflux),
+					options...)
+				if err != nil {
+					log.Fatalf("cannot open the output file for key %s", newflux)
+				}
 
-			n++
+				atomic.AddInt32(&n, 1)
 
-			if n > 1 {
-				jobDone.Add(1)
-			}
-
-			go func() {
+				if atomic.LoadInt32(&n) > 1 {
+					jobDone.Add(1)
+				}
 				out.Recycle()
 				jobDone.Done()
-			}()
+			}(newflux)
 		}
 	}()
 
diff --git a/pkg/obitools/obidistribute/options.go b/pkg/obitools/obidistribute/options.go
index 96100cd..64d20e2 100644
--- a/pkg/obitools/obidistribute/options.go
+++ b/pkg/obitools/obidistribute/options.go
@@ -13,20 +13,29 @@ import (
 var _FilenamePattern = ""
 var _SequenceClassifierTag = ""
 var _BatchCount = 0
+var _HashSize = 0
 
 func DistributeOptionSet(options *getoptions.GetOpt) {
 	options.StringVar(&_FilenamePattern, "pattern", _FilenamePattern,
 		options.Alias("p"),
 		options.Required("You must provide at pattern for the file names "),
-		options.Description("The N first sequence records of the file are discarded from the analysis and not reported to the output file."))
+		options.Description("The template used to build the names of the output files. "+
+			"The variable part is represented by '%s'. "+
+			"Example : toto_%s.fastq."))
 
 	options.StringVar(&_SequenceClassifierTag, "classifier", _SequenceClassifierTag,
 		options.Alias("c"),
-		options.Description("The N first sequence records of the file are discarded from the analysis and not reported to the output file."))
+		options.Description("The name of a tag annotating thes sequences. "+
+			"The name must corresponds to a string, a integer or a boolean value. "+
+			"That value will be used to dispatch sequences amoong the different files"))
 
-	options.IntVar(&_BatchCount, "batch", 0,
+	options.IntVar(&_BatchCount, "batches", 0,
 		options.Alias("n"),
-		options.Description("The N first sequence records of the file are discarded from the analysis and not reported to the output file."))
+		options.Description("Indicates in how many batches the input file must bee splitted."))
+
+	options.IntVar(&_HashSize, "hash", 0,
+		options.Alias("H"),
+		options.Description("Indicates to split the input into at most <n> batch based on a hash code of the seequence."))
 }
 
 func OptionSet(options *getoptions.GetOpt) {
@@ -41,10 +50,11 @@ func CLISequenceClassifier() obiseq.SequenceClassifier {
 		return obiseq.AnnotationClassifier(_SequenceClassifierTag)
 	case _BatchCount > 0:
 		return obiseq.RotateClassifier(_BatchCount)
-
+	case _HashSize > 0:
+		return obiseq.HashClassifier(_HashSize)
 	}
 
-	log.Fatal("one of the options --classifier or --batch must be specified")
+	log.Fatal("one of the options --classifier, -- hash or --batch must be specified")
 	return nil
 }