diff --git a/.gitignore b/.gitignore
index 7153307..5849212 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,4 +1,4 @@
 exe/
 *.exe
 *.swp
-
+/bb
diff --git a/go.mod b/go.mod
index 4a74aaf..5f4a84d 100644
--- a/go.mod
+++ b/go.mod
@@ -2,4 +2,4 @@ module surdeus.su/util/bb
 
 go 1.22.3
 
-require surdeus.su/core/cli v0.3.0
+require surdeus.su/core/cli v0.5.0
diff --git a/go.sum b/go.sum
index 1bd3ad5..7ab104d 100644
--- a/go.sum
+++ b/go.sum
@@ -2,3 +2,5 @@ surdeus.su/core/cli v0.1.2 h1:qPzjawqPyZsO4Z5SaA1u141recVE65yioA83Qs7Jecs=
 surdeus.su/core/cli v0.1.2/go.mod h1:r9JtQz3aEJzpYzMaNUNQHJoYkoWKNPi047qhd5uGlmA=
 surdeus.su/core/cli v0.3.0 h1:/2UfObbesg3/2FPn/9Ys/w/H2XOxOv72ehidwctAGdM=
 surdeus.su/core/cli v0.3.0/go.mod h1:r9JtQz3aEJzpYzMaNUNQHJoYkoWKNPi047qhd5uGlmA=
+surdeus.su/core/cli v0.5.0 h1:jYvE0JVDikFT9FhWGV3wIAcMgByziAVxTwsVUwWkeHs=
+surdeus.su/core/cli v0.5.0/go.mod h1:r9JtQz3aEJzpYzMaNUNQHJoYkoWKNPi047qhd5uGlmA=
diff --git a/tool/cat/cat.go b/tool/cat/cat.go
index 950962b..9a8410c 100644
--- a/tool/cat/cat.go
+++ b/tool/cat/cat.go
@@ -1,13 +1,15 @@
 package cat
+
 /* Concatenate files in "stdout". */
-import(
-	"os"
-	"io"
+import (
 	"fmt"
+	"io"
+	"os"
+
 	"surdeus.su/core/cli/mtool"
 )
 
-var(
+var (
 	blockSize int
 )
 
@@ -37,7 +39,7 @@ func fcat(f *os.File) error {
 	return nil
 }
 
-func Run(flags *mtool.Flags) {	
+func Run(flags *mtool.Flags) {
 	flags.IntVar(&blockSize, "bs", 512, "block size")
 	flags.Parse()
 	args := flags.Args()