diff --git a/command.go b/command.go
index 6045b2e..4727d28 100644
--- a/command.go
+++ b/command.go
@@ -4,7 +4,6 @@ import(
   "log"
   "os"
   "io"
-  "path/filepath"
 )
 
 func cmdHead(config *configCollect) {
@@ -30,13 +29,6 @@ func cmdHead(config *configCollect) {
 }
 
 
-type LsWalker struct { }
-func (lw* LsWalker) onDir(dn *DirNode) {
-  log.Println(dn.String())
-}
-func (lw* LsWalker) onFile(fn *FileNode) {
-  log.Println(fn.String())
-}
 func cmdLs(config *configCollect) {
   en := NewEntryNode(config)
   en.Walk(new(LsWalker))
@@ -62,24 +54,6 @@ func cmdCpFile(config *configCollect) {
   }
 }
 
-type CopyWalker struct { }
-func (cw* CopyWalker) onDir(dn *DirNode) {
-  err := os.MkdirAll(filepath.Join(dn.Config.Dest, dn.AbsolutePath), os.ModePerm)
-  if err != nil { log.Fatal(err) }
-  log.Println(dn.String())
-}
-func (cw* CopyWalker) onFile(fn *FileNode) {
-  fn.Parse()
-  file, err := os.Create(filepath.Join(fn.Config.Dest, fn.AbsolutePath))
-  if err != nil { log.Fatal(err) }
-  defer file.Close()
-  written, err := io.Copy(file, fn)
-  if err != nil { log.Fatal(err) }
-  if uint64(written) != fn.Elem.FileSize {
-    log.Fatal(written, "bytes written,", fn.Elem.FileSize, "bytes expected")
-  }
-  log.Println(fn.String())
-}
 func cmdCpDir(config *configCollect) {
   en := NewEntryNode(config)
   en.Walk(new(CopyWalker))
diff --git a/copy_walker.go b/copy_walker.go
new file mode 100644
index 0000000..c09d6b4
--- /dev/null
+++ b/copy_walker.go
@@ -0,0 +1,27 @@
+package main
+
+import (
+  "log"
+  "os"
+  "path/filepath"
+  "io"
+)
+
+type CopyWalker struct { }
+func (cw* CopyWalker) onDir(dn *DirNode) {
+  err := os.MkdirAll(filepath.Join(dn.Config.Dest, dn.AbsolutePath), os.ModePerm)
+  if err != nil { log.Fatal(err) }
+  log.Println(dn.String())
+}
+func (cw* CopyWalker) onFile(fn *FileNode) {
+  fn.Parse()
+  file, err := os.Create(filepath.Join(fn.Config.Dest, fn.AbsolutePath))
+  if err != nil { log.Fatal(err) }
+  defer file.Close()
+  written, err := io.Copy(file, fn)
+  if err != nil { log.Fatal(err) }
+  if uint64(written) != fn.Elem.FileSize {
+    log.Fatal(written, "bytes written,", fn.Elem.FileSize, "bytes expected")
+  }
+  log.Println(fn.String())
+}
diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..999fa28
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,8 @@
+module git.deuxfleurs.fr/quentin/seafile_recovery
+
+go 1.15
+
+require (
+	github.com/aws/aws-sdk-go v1.38.25
+	github.com/docopt/docopt-go v0.0.0-20180111231733-ee0de3bc6815
+)
diff --git a/go.sum b/go.sum
new file mode 100644
index 0000000..5dccb96
--- /dev/null
+++ b/go.sum
@@ -0,0 +1,23 @@
+github.com/aws/aws-sdk-go v1.38.25 h1:aNjeh7+MON05cZPtZ6do+KxVT67jPOSQXANA46gOQao=
+github.com/aws/aws-sdk-go v1.38.25/go.mod h1:hcU610XS61/+aQV88ixoOzUoG7v3b31pl2zKMmprdro=
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/docopt/docopt-go v0.0.0-20180111231733-ee0de3bc6815 h1:bWDMxwH3px2JBh6AyO7hdCn/PkvCZXii8TGj7sbtEbQ=
+github.com/docopt/docopt-go v0.0.0-20180111231733-ee0de3bc6815/go.mod h1:WwZ+bS3ebgob9U8Nd0kOddGdZWjyMGR8Wziv+TBNwSE=
+github.com/jmespath/go-jmespath v0.4.0 h1:BEgLn5cpjn8UN1mAw4NjwDrS35OdebyEtFe+9YPoQUg=
+github.com/jmespath/go-jmespath v0.4.0/go.mod h1:T8mJZnbsbmF+m6zOOFylbeCJqk5+pHWvzYPziyZiYoo=
+github.com/jmespath/go-jmespath/internal/testify v1.5.1/go.mod h1:L3OGu8Wl2/fWfCI6z80xFu9LTZmf1ZRjMHUOPmWr69U=
+github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
+golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
+golang.org/x/net v0.0.0-20201110031124-69a78807bb2b/go.mod h1:sp8m0HH+o8qH0wwXwYZr8TS3Oi6o0r6Gce1SSxlDquU=
+golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20200930185726-fdedc70b468f/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
+golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
+golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v2 v2.2.8/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
diff --git a/ls_walker.go b/ls_walker.go
new file mode 100644
index 0000000..199a370
--- /dev/null
+++ b/ls_walker.go
@@ -0,0 +1,11 @@
+package main
+
+import ("log")
+
+type LsWalker struct { }
+func (lw* LsWalker) onDir(dn *DirNode) {
+  log.Println(dn.String())
+}
+func (lw* LsWalker) onFile(fn *FileNode) {
+  log.Println(fn.String())
+}
diff --git a/s3_walker.go b/s3_walker.go
new file mode 100644
index 0000000..e75f9ce
--- /dev/null
+++ b/s3_walker.go
@@ -0,0 +1,11 @@
+package main
+
+import (
+  "github.com/aws/aws-sdk-go/service/s3"
+)
+
+type S3Walker struct { }
+func (sw* S3Walker) onDir(dn *DirNode) {
+}
+func (sw* S3Walker) onFile(fn *FileNode) {
+}