diff --git a/README.md b/README.md
index 7fffab3..6761b2f 100644
--- a/README.md
+++ b/README.md
@@ -3,7 +3,7 @@
 Basic and simple packaging system
 
 Designed to be used by anyone and deployed anywhere,
-it is a very basic packaging system without much functionnality but very portable
+it is a very basic packaging system with basic functionnality but very portable
 
 Official repo: [http://zpkg.zawz.net](http://zpkg.zawz.net)
 
diff --git a/src/install.sh b/src/install.sh
index d173978..0107b4a 100644
--- a/src/install.sh
+++ b/src/install.sh
@@ -21,26 +21,14 @@ add_package_entry()
 }
 
 # $1 = source_dir, $2 = dest_dir, $3 = prefix for exec
-move_files()
-{
-  # create dirs
-  FOLDERS=$(find "$1" -mindepth 1 -type d | sed "s|^$1/||g")
-  echo "$FOLDERS" | while read -r I
-  do
-    $3 mkdir -p "$2/$I"
-  done
-
-  # move files
-  FILES=$(find "$1" -mindepth 1 ! -type d | sed "s|^$1/||g")
-  echo "$FILES" | while read -r I
-  do
-    $3 mv "$1/$I" "$2/$I"
-  done
+copy_files() {
+  $3 cp -r "$1/." "$2"
 }
 
 # $1 = package , $2 = prefix
 install_package()
 {
+  echo "Installing $1"
   tmpdir="/tmp/zpkg_$(random_string 5)"
   mkdir -p "$tmpdir"
   (
@@ -48,8 +36,8 @@ install_package()
     fetch_package "$1" || { echo "Package '$1' not found" >&2 && return 1; }
     $2 cp "$1.tar.$extension" "$PKG_PATH"
     unpack "$1.tar.$extension" || return $?
-    move_files ROOT / $2 2>/dev/null
-    move_files HOME "$HOME" 2>/dev/null
+    copy_files ROOT / $2 2>/dev/null
+    copy_files HOME "$HOME" 2>/dev/null
     add_package_entry "$1" $2
   )
   ret=$?
diff --git a/src/main.sh b/src/main.sh
index 56061ea..ac99712 100644
--- a/src/main.sh
+++ b/src/main.sh
@@ -66,8 +66,10 @@ install)
     echo "Installing packages: $pkglist"
     for I in $pkglist
     do
-      is_installed $I && remove_package $I $sudo
-      install_package $I $sudo
+      if is_installed $I
+      then upgrade_package $I $sudo
+      else install_package $I $sudo
+      fi
     done
   fi
   ;;
@@ -89,7 +91,7 @@ update)
   o_pkg=$(outdated_packages)
   if [ -n "$r_pkg" ]
   then
-    echo "Removing packages: "$r_pkg
+    echo "Packages to remove: "$r_pkg
     for I in $r_pkg
     do
       remove_package $I $sudo
@@ -97,11 +99,10 @@ update)
   fi
   if [ -n "$o_pkg" ]
   then
-    echo "Updating packages: "$o_pkg
+    echo "Packages to update: "$o_pkg
     for I in $o_pkg
     do
-      remove_package $I $sudo
-      install_package $I $sudo
+      upgrade_package $I $sudo
     done
   fi
   ;;
diff --git a/src/remove.sh b/src/remove.sh
index f7fce64..707b182 100644
--- a/src/remove.sh
+++ b/src/remove.sh
@@ -1,12 +1,13 @@
 #!/bin/sh
 
 # files from stdin
-# $1 = prefix
+# $1 = from where , $2 = prefix
 delete_files()
 {
+  cd "$1" || return $?
   while read -r in
   do
-    [ -n "$in" ] && $1 rm -d "$in" 2>/dev/null
+    [ -n "$in" ] && $2 rm -d "$in" 2>/dev/null
   done
 }
 
@@ -22,14 +23,10 @@ remove_package()
   fi
   echo "Removing $1"
 
-  ( # delete root files
-    cd /
-    $pcompress -dc "$archive" | tar -tf - ROOT 2>/dev/null | sed 's|^ROOT/||g' | tac | delete_files $2
-  )
-  ( # delete home files
-    cd "$HOME"
-    $pcompress -dc "$archive" | tar -tf - HOME 2>/dev/null | sed 's|^HOME/||g' | tac | delete_files
-  )
+  list=$($pcompress -dc "$archive" | tar -tf - 2>/dev/null)
+
+  echo "$list" | grep "^ROOT/" | sed 's|^ROOT/||g' | tac | delete_files / $2
+  echo "$list" | grep "^HOME/" | sed 's|^HOME/||g' | tac | delete_files "$HOME"
 
   $2 rm "$archive" 2>/dev/null
   $2 sed -i "/^$1 /d" installed
diff --git a/src/upgrade.sh b/src/upgrade.sh
new file mode 100644
index 0000000..6f92223
--- /dev/null
+++ b/src/upgrade.sh
@@ -0,0 +1,38 @@
+#!/bin/sh
+
+# stdin: old list
+# $1 = old list , $1 = new path
+to_delete()
+{
+  find "$2" -type d 2>/dev/null | sed 's|$|/|g' > tmplist
+  find "$2" -type f 2>/dev/null >> tmplist
+  sort tmplist > list
+  diff --new-line-format="" --unchanged-line-format="" "$1" list
+  rm tmplist list
+}
+
+# $1 = package , $2 = prefix
+upgrade_package()
+{
+  echo "Updating $1"
+  tmpdir="/tmp/zpkg_$(random_string 5)"
+  mkdir -p "$tmpdir"
+  (
+    # fetch package
+    cd "$tmpdir"
+    fetch_package "$1" || { echo "Package '$1' not found" >&2 && return 1; }
+    unpack "$1.tar.$extension" || return $?
+
+    oldlist=$($pcompress -dc "$PKG_PATH/$1.tar.$extension" | tar -tf - 2>/dev/null | sort)
+    echo "$oldlist" | grep "^ROOT/" | to_delete - ROOT | sed 's|^ROOT/||g' | tac | delete_files / $2
+    echo "$oldlist" | grep "^HOME/" | to_delete - HOME | sed 's|^HOME/||g' | tac | delete_files "$HOME"
+
+    copy_files ROOT / $2 2>/dev/null
+    copy_files HOME "$HOME" 2>/dev/null
+    $2 cp "$1.tar.$extension" "$PKG_PATH"
+    add_package_entry "$1" $2
+  )
+  ret=$?
+  rm -rd "$tmpdir" 2>/dev/null
+  return $ret
+}