diff --git a/README.md b/README.md
index 9e83934..1412d96 100644
--- a/README.md
+++ b/README.md
@@ -28,6 +28,12 @@ bootstrap file :
 dotinstall uninstall bootstrap
 ```
 
+Or update with `update` even in git mode
+
+```
+dotinstall update bootstrap
+```
+
 ## Boostrap file syntax
 
 `bootstrap` is a simple bash script sourced by `dotinstall`. The `bootstrap`
@@ -128,6 +134,23 @@ define_env "NOTMUCH_CONFIG" "~/.config/notmuch"
      displayed.
  - `OVERWRITE_FILE` : do the same with file
 
+## Return code
+
+This script return 0 if there is not error.
+
+ - **1** : no bootstrap specified.
+ - **2** : boostrap file not found
+
+### Git relative error codes
+
+ - **20** : can't clone dotfile git repository.
+ - **24** : can't update dotfile git repository.
+ - **25** : local git repository does not exist.
+
+### Script relative error code
+
+ - **128** : a binary checked by `chek_bin()` is not present
+
 ## Licence
 
 This software is licenced under the GNU-GPL 3 licence, you can found a copy of
diff --git a/src/dotinstall.sh b/src/dotinstall.sh
index 5126c4e..9469260 100755
--- a/src/dotinstall.sh
+++ b/src/dotinstall.sh
@@ -2,10 +2,12 @@
 
 # Personnal Dotfiles install script
 
-BIN_DIRECTORY="${HOME}/.local/bin/"
-LIB_DIRECTORY="${HOME}/.local/lib/"
+BIN_DIRECTORY="${HOME}/.local/bin"
+LIB_DIRECTORY="${HOME}/.local/lib"
 SYD_DIRECTORY="${HOME}/.config/systemd/user"
-DOTREPO="${HOME}/.config/dotrepo/"
+CACHE_DIR="${HOME}/.cache/dotinstall"
+
+DOTREPO="${HOME}/.config/dotrepo"
 ENV_FILE="${HOME}/.config/environment"
 
 # DEFAULT VALUES
@@ -14,6 +16,7 @@ OVERWRITE_FILE=0
 
 repository=""
 install=1
+update=0
 
 usage ()
 {
@@ -147,7 +150,8 @@ private:create_symblink ()
 private:clone_repository ()
 {
     # Clone a git repository and test if it has a bootstrap file
-    # $* url
+    # $1 url
+    # $2 local repository
     # return : local directory
 
     local ret
@@ -155,6 +159,19 @@ private:clone_repository ()
     [[ $? -ne 0 ]] && die "Can't clone_repository : $ret" 20 0
 }
 
+private:update_repository ()
+{
+    # Update a git repository
+    # $1 : local repository
+    
+    [ ! -d "$1" ] && die "Git update : directory $1 does not exist" 25 0
+    local current_dir=$(pwd)
+    local ret
+    cd "$1"
+    ret=$(git pull 2>&1)
+    [[ $? -ne 0 ]] && die "Can't update repository : $ret" 24 0
+}
+
 process_dirs () {
 
     # Process a directory than contains subdir, create symblink from each subdir
@@ -166,7 +183,7 @@ process_dirs () {
     local dest="${repository}/$1"
     printf "\nProcess directory %s\n" "$1"
 
-    [ ! -d "$dest" ] && { error "  -> source is not a directory"; return; }
+    [ ! -d "$dest" ] && { error "  -> source is not a directory $dest"; return; }
     [ ! -d "$dest" ] && { error "  -> destination is not a directory"; return; }
 
     while read d
@@ -309,32 +326,82 @@ define_env ()
 
 ## create bin directory
 [ ! -d $BIN_DIRECTORY ] && mkdir -p $BIN_DIRECTORY || printf "bin exist\n"
+[ ! -d $CACHE_DIR ] && mkdir -p $CACHE_DIR || printf "cache exist\n"
+# define mode : install, uninstall or update
+case $1 in
+    "uninstall")
+        install=0
+        printf "Activate uninstall mode\n"
+        shift
+        ;;
 
-# Test parameters : we need to know if it's a git repo or a file
-[[ $1 == "uninstall" || $1 == "-u" ]] && { install=0; printf "Activate uninstall mode\n"; shift; }
-[ "$*" = "" ] && die "You must specify a bootstrap file" 10 1
+    "update")
+        update=1;
+        printf "Activate update mode\n"
+        shift
+        ;;
+esac
+
+[ "$*" = "" ] && die "You must specify a bootstrap file or repo" 1 1
 
 if [[ $* =~ ^https://.*\.git$ || $* =~ ^ssh://.*\.git$ ]]
 then
-    bin_check "git"
+    check_bin "git"
     
     # Check
-    localdir="${DOTREPO}/$(basename $* .git)"
-    [ -d "$localdir" ] && die "destination folder for git repository already exist" 21 0
-    
-    private:clone_repository "$*" "$localdir"
-    if [ -f "${localdir}/bootstrap" ]
+    localrepo="${DOTREPO}/$(basename $* .git)"
+    if [ $update -eq 1 ]
     then
-        $0 "${localdir}/bootstrap"
-        exit $?
+        private:update_repository "$localrepo"
     else
-        die "Can't find a \`boostrap\` file in ${repo}" 22 0
+        if [ $install -eq 1 ]
+        then
+            private:clone_repository "$*" "$localrepo"
+        fi
     fi
+    bootstrap_file="${localrepo}/bootstrap"
 else
-    [ ! -f "$*" ] && die "$* does not exist" 10 1
-    private:get_bootstrap_path "$*"
-
-    # Include bootstrap
-    source $*
+    bootstrap_file="$*"
 fi
+
+[ ! -f "$bootstrap_file" ] && die "$bootstrap_file does not exist" 2 1
+
+private:get_bootstrap_path "$bootstrap_file"
+
+cache_file="${CACHE_DIR}/$(echo $repository | tr '/' '_')"
+
+if [ $update -eq 1 ]
+then
+    # Update mode
+    if [ -f "$cache_file" ]
+    then
+        if [ $(diff "$bootstrap_file" "$cache_file" > /dev/null; echo $?;) -eq 0 ]
+        then
+            printf "There is no difference between cached copy and the bootstrap file\n";
+            exit 0
+        else
+            # Uninstall old files
+            install=0
+            source "$cache_file"
+            rm "$cache_file"
+            install=1
+        fi
+    else
+        error "Can't found cached copy of bootstrap file, just install"
+    fi
+fi
+
+cp "$bootstrap_file" "$cache_file"
+
+# Include bootstrap
+source "$bootstrap_file"
+
+# remove cached file and repo if uninstall
+if [ $install -eq 0 ]
+then
+    printf "\nRemove files for complete uninstall\n"
+    rm $cache_file
+    rm -rf $repository
+fi
+
 exit 0