diff --git a/catcli/__init__.py b/catcli/__init__.py
index f63e2b6..2f1d317 100644
--- a/catcli/__init__.py
+++ b/catcli/__init__.py
@@ -5,7 +5,7 @@ Copyright (c) 2017, deadc0de6
 
 import sys
 
-__version__ = '0.4.6'
+__version__ = '0.5.4'
 
 
 def main():
diff --git a/catcli/catalog.py b/catcli/catalog.py
index 3eb2b07..9eea7c5 100644
--- a/catcli/catalog.py
+++ b/catcli/catalog.py
@@ -22,16 +22,15 @@ class Catalog:
         self.verbose = verbose  # verbosity
         self.force = force  # force overwrite if exists
         self.metanode = None
-        # prefer json for git versioning
         self.pickle = pickle
 
     def set_metanode(self, metanode):
-        ''' remove the metanode until tree is re-written '''
+        '''remove the metanode until tree is re-written'''
         self.metanode = metanode
         self.metanode.parent = None
 
     def restore(self):
-        ''' restore the catalog '''
+        '''restore the catalog'''
         if not self.path:
             return None
         if not os.path.exists(self.path):
@@ -41,7 +40,7 @@ class Catalog:
         return self._restore_json(open(self.path, 'r').read())
 
     def save(self, node):
-        ''' save the catalog '''
+        '''save the catalog'''
         if not self.path:
             Logger.err('Path not defined')
             return False
@@ -49,7 +48,7 @@ class Catalog:
         if d and not os.path.exists(d):
             os.makedirs(d)
         elif os.path.exists(self.path) and not self.force:
-            if not utils.ask('Overwrite \"{}\"'.format(self.path)):
+            if not utils.ask('Update catalog \"{}\"'.format(self.path)):
                 Logger.info('Catalog not saved')
                 return False
         if d and not os.path.exists(d):
@@ -62,14 +61,22 @@ class Catalog:
         return self._save_json(node)
 
     def _save_pickle(self, node):
-        ''' pickle the catalog'''
+        '''pickle the catalog'''
         pickle.dump(node, open(self.path, 'wb'))
         if self.verbose:
             Logger.info('Catalog saved to pickle \"{}\"'.format(self.path))
         return True
 
+    def _restore_pickle(self):
+        '''restore the pickled tree'''
+        root = pickle.load(open(self.path, 'rb'))
+        if self.verbose:
+            m = 'Catalog imported from pickle \"{}\"'.format(self.path)
+            Logger.info(m)
+        return root
+
     def _save_json(self, node):
-        ''' export the catalog in json '''
+        '''export the catalog in json'''
         exp = JsonExporter(indent=2, sort_keys=True)
         with open(self.path, 'w') as f:
             exp.write(node, f)
@@ -77,16 +84,8 @@ class Catalog:
             Logger.info('Catalog saved to json \"{}\"'.format(self.path))
         return True
 
-    def _restore_pickle(self):
-        ''' restore the pickled tree '''
-        root = pickle.load(open(self.path, 'rb'))
-        if self.verbose:
-            m = 'Catalog imported from pickle \"{}\"'.format(self.path)
-            Logger.info(m)
-        return root
-
     def _restore_json(self, string):
-        ''' restore the tree from json '''
+        '''restore the tree from json'''
         imp = JsonImporter()
         root = imp.import_(string)
         if self.verbose:
diff --git a/catcli/catcli.py b/catcli/catcli.py
index 3612461..43f28fd 100755
--- a/catcli/catcli.py
+++ b/catcli/catcli.py
@@ -37,6 +37,7 @@ USAGE = """
 
 Usage:
     {1} index  [--catalog=<path>] [--meta=<meta>...] [-acfuV] <name> <path>
+    {1} update [--catalog=<path>] [-acfuV] <name> <path>
     {1} ls     [--catalog=<path>] [-arVS] [<path>]
     {1} find   [--catalog=<path>] [-abV] <term>
     {1} rm     [--catalog=<path>] [-fV] <storage>
@@ -49,42 +50,69 @@ Usage:
     {1} --version
 
 Options:
-    --catalog=<path>    Path to the catalog [default: {2}].
-    --meta=<meta>       Additional attribute to store [default: ].
-    -u --subsize        Store size of folders [default: False].
-    -a --archive        Handle archive file [default: False].
-    -f --force          Force overwrite [default: False].
-    -b --script         Output script to manage found file(s) [default: False].
-    -S --sortsize       Sort by size, largest first [default: False].
-    -c --hash           Calculate md5 hash [default: False].
-    -r --recursive      Recursive [default: False].
-    -V --verbose        Be verbose [default: False].
-    -v --version        Show version.
-    -h --help           Show this screen.
+    --catalog=<path>  Path to the catalog [default: {2}].
+    --meta=<meta>     Additional attribute to store [default: ].
+    -u --subsize      Store size of directories [default: False].
+    -a --archive      Handle archive file [default: False].
+    -f --force        Do not ask when updating the catalog [default: False].
+    -b --script       Output script to manage found file(s) [default: False].
+    -S --sortsize     Sort by size, largest first [default: False].
+    -c --hash         Calculate md5 hash [default: False].
+    -r --recursive    Recursive [default: False].
+    -V --verbose      Be verbose [default: False].
+    -v --version      Show version.
+    -h --help         Show this screen.
 """.format(BANNER, NAME, CATALOGPATH)
 
 
-def cmd_index(args, noder, catalog, top):
+def cmd_index(args, noder, catalog, top, debug=False):
     path = args['<path>']
     name = args['<name>']
     nohash = not args['--hash']
     subsize = args['--subsize']
     if not os.path.exists(path):
         Logger.err('\"{}\" does not exist'.format(path))
-        return False
+        return
     if name in noder.get_storage_names(top):
-        Logger.err('storage named \"{}\" already exist'.format(name))
-        return False
+        if not ask('Overwrite storage \"{}\"'.format(name)):
+            Logger.err('storage named \"{}\" already exist'.format(name))
+            return
+        node = noder.get_storage_node(top, name)
+        node.parent = None
     start = datetime.datetime.now()
-    walker = Walker(noder, nohash=nohash)
-    attr = noder.clean_storage_attr(args['--meta'])
+    walker = Walker(noder, nohash=nohash, debug=debug)
+    attr = noder.format_storage_attr(args['--meta'])
     root = noder.storage_node(name, path, parent=top, attr=attr)
-    _, cnt = walker.index(path, name, parent=root, parentpath=path)
+    _, cnt = walker.index(path, root, name)
     if subsize:
         noder.rec_size(root)
     stop = datetime.datetime.now()
     Logger.info('Indexed {} file(s) in {}'.format(cnt, stop - start))
-    catalog.save(top)
+    if cnt > 0:
+        catalog.save(top)
+
+
+def cmd_update(args, noder, catalog, top, debug=False):
+    path = args['<path>']
+    name = args['<name>']
+    nohash = not args['--hash']
+    subsize = args['--subsize']
+    if not os.path.exists(path):
+        Logger.err('\"{}\" does not exist'.format(path))
+        return
+    root = noder.get_storage_node(top, name)
+    if not root:
+        Logger.err('storage named \"{}\" does not exist'.format(name))
+        return
+    start = datetime.datetime.now()
+    walker = Walker(noder, nohash=nohash, debug=debug)
+    cnt = walker.reindex(path, root, top)
+    if subsize:
+        noder.rec_size(root)
+    stop = datetime.datetime.now()
+    Logger.info('updated {} file(s) in {}'.format(cnt, stop - start))
+    if cnt > 0:
+        catalog.save(top)
 
 
 def cmd_ls(args, noder, top):
@@ -104,15 +132,14 @@ def cmd_ls(args, noder, top):
 
 
 def cmd_rm(args, noder, catalog, top):
-    what = args['<storage>']
-    storages = list(x.name for x in top.children)
-    if what in storages:
-        node = next(filter(lambda x: x.name == what, top.children))
+    name = args['<storage>']
+    node = noder.get_storage_node(top, name)
+    if node:
         node.parent = None
         if catalog.save(top):
-            Logger.info('Storage \"{}\" removed'.format(what))
+            Logger.info('Storage \"{}\" removed'.format(name))
     else:
-        Logger.err('Storage named \"{}\" does not exist'.format(what))
+        Logger.err('Storage named \"{}\" does not exist'.format(name))
     return top
 
 
@@ -201,7 +228,9 @@ def main():
 
     # parse command
     if args['index']:
-        cmd_index(args, noder, catalog, top)
+        cmd_index(args, noder, catalog, top, debug=args['--verbose'])
+    if args['update']:
+        cmd_update(args, noder, catalog, top, debug=args['--verbose'])
     elif args['find']:
         cmd_find(args, noder, top)
     elif args['tree']:
@@ -221,7 +250,7 @@ def main():
 
 
 if __name__ == '__main__':
-    ''' entry point '''
+    '''entry point'''
     if main():
         sys.exit(0)
     sys.exit(1)
diff --git a/catcli/decomp.py b/catcli/decomp.py
index fc69ac5..9963888 100644
--- a/catcli/decomp.py
+++ b/catcli/decomp.py
@@ -29,22 +29,25 @@ class Decomp:
             'zip': self._zip}
 
     def get_format(self):
+        '''return list of supported extensions'''
         return list(self.ext.keys())
 
     def get_names(self, path):
-        ''' get tree of compressed archive '''
+        '''get tree of compressed archive'''
         ext = os.path.splitext(path)[1][1:]
         if ext in list(self.ext.keys()):
             return self.ext[ext](path)
         return None
 
     def _tar(self, path):
+        '''return list of file names in tar'''
         if not tarfile.is_tarfile(path):
             return None
         tar = tarfile.open(path, "r")
         return tar.getnames()
 
     def _zip(self, path):
+        '''return list of file names in zip'''
         if not zipfile.is_zipfile(path):
             return None
         z = zipfile.ZipFile(path)
diff --git a/catcli/logger.py b/catcli/logger.py
index 819acd5..5500a59 100644
--- a/catcli/logger.py
+++ b/catcli/logger.py
@@ -29,7 +29,7 @@ class Logger:
     # node specific output
     ######################################################################
     def storage(pre, name, attr):
-        ''' print a storage node '''
+        '''print a storage node'''
         end = ''
         if attr:
             end = ' {}({}){}'.format(Logger.GRAY, attr, Logger.RESET)
@@ -38,13 +38,13 @@ class Logger:
         sys.stdout.write('{}\n'.format(s))
 
     def file(pre, name, attr):
-        ''' print a file node '''
+        '''print a file node'''
         s = '{}{}'.format(pre, name)
         s += ' {}[{}]{}'.format(Logger.GRAY, attr, Logger.RESET)
         sys.stdout.write('{}\n'.format(s))
 
     def dir(pre, name, depth='', attr=None):
-        ''' print a directory node '''
+        '''print a directory node'''
         end = []
         if depth != '':
             end.append('nbfiles:{}'.format(depth))
@@ -65,27 +65,28 @@ class Logger:
     # generic output
     ######################################################################
     def out(string):
-        ''' to stdout '''
+        '''to stdout'''
         sys.stdout.write('{}\n'.format(string))
 
     def log(string):
-        ''' to stderr '''
+        '''to stderr'''
         sys.stderr.write('{}\n'.format(string))
 
     def info(string):
-        ''' to stderr in color '''
+        '''to stderr in color'''
         s = '{}{}{}'.format(Logger.MAGENTA, string, Logger.RESET)
         sys.stderr.write('{}\n'.format(s))
 
     def err(string):
-        ''' to stderr in RED '''
+        '''to stderr in RED'''
         s = '{}{}{}'.format(Logger.RED, string, Logger.RESET)
         sys.stderr.write('{}\n'.format(s))
 
     def progr(string):
-        ''' print progress '''
+        '''print progress'''
         sys.stderr.write('{}\r'.format(string))
         sys.stderr.flush()
 
     def bold(string):
+        '''make it bold'''
         return '{}{}{}'.format(Logger.BOLD, string, Logger.RESET)
diff --git a/catcli/noder.py b/catcli/noder.py
index 2f0a457..2a85d69 100644
--- a/catcli/noder.py
+++ b/catcli/noder.py
@@ -29,7 +29,7 @@ class Noder:
 
     TOPNAME = 'top'
     METANAME = 'meta'
-    TYPE_TOP = 'top'  # tip top ;-)
+    TYPE_TOP = 'top'
     TYPE_FILE = 'file'
     TYPE_DIR = 'dir'
     TYPE_ARC = 'arc'
@@ -44,36 +44,91 @@ class Noder:
         if self.arc:
             self.decomp = Decomp()
 
-    def set_hashing(self, val):
-        self.hash = val
-
     def get_storage_names(self, top):
-        ''' return a list of all storage names '''
+        '''return a list of all storage names'''
         return [x.name for x in list(top.children)]
 
-    def clean_storage_attr(self, attr):
-        if not attr:
-            return ''
-        return ', '.join(attr)
+    def get_storage_node(self, top, name):
+        '''return the storage node if any'''
+        for n in top.children:
+            if n.type != self.TYPE_STORAGE:
+                continue
+            if n.name == name:
+                return n
+        return None
 
-    def get_node(self, top, path):
-        ''' get the node at path '''
+    def get_node(self, top, path, quiet=False):
+        '''get the node by internal tree path'''
         r = anytree.resolver.Resolver('name')
         try:
             return r.get(top, path)
         except anytree.resolver.ChildResolverError:
-            Logger.err('No node at path \"{}\"'.format(path))
+            if not quiet:
+                Logger.err('No node at path \"{}\"'.format(path))
             return None
 
+    def get_node_if_newer(self, top, path, maccess):
+        '''return the node (if any) and if path is newer'''
+        treepath = path.lstrip(os.sep)
+        node = self.get_node(top, treepath, quiet=True)
+        if not node:
+            # node does not exist
+            return None, True
+        if not node.maccess:
+            # force re-indexing if no maccess
+            return node, True
+        old_maccess = node.maccess
+        if float(maccess) > float(old_maccess):
+            return node, True
+        return node, False
+
+    def get_meta_node(self, top):
+        '''return the meta node if any'''
+        try:
+            return next(filter(lambda x: x.type == self.TYPE_META,
+                        top.children))
+        except StopIteration:
+            return None
+
+    def rec_size(self, node):
+        '''recursively traverse tree and store dir size'''
+        if self.verbose:
+            Logger.info('getting directory size recursively')
+        if node.type == self.TYPE_FILE:
+            return node.size
+        size = 0
+        for i in node.children:
+            if node.type == self.TYPE_DIR:
+                size += self.rec_size(i)
+            if node.type == self.TYPE_STORAGE:
+                self.rec_size(i)
+            else:
+                continue
+        node.size = size
+        return size
+
+    ###############################################################
+    # public helpers
+    ###############################################################
+    def format_storage_attr(self, attr):
+        '''format the storage attr for saving'''
+        if not attr:
+            return ''
+        return ', '.join(attr)
+
+    def set_hashing(self, val):
+        '''hash files when indexing'''
+        self.hash = val
+
     ###############################################################
     # node creationg
     ###############################################################
     def new_top_node(self):
-        ''' create a new top node'''
+        '''create a new top node'''
         return anytree.AnyNode(name=self.TOPNAME, type=self.TYPE_TOP)
 
     def update_metanode(self, meta):
-        ''' create or update meta node information '''
+        '''create or update meta node information'''
         epoch = int(time.time())
         if not meta:
             attr = {}
@@ -86,7 +141,7 @@ class Noder:
         return meta
 
     def file_node(self, name, path, parent, storagepath):
-        ''' create a new node representing a file '''
+        '''create a new node representing a file'''
         if not os.path.exists(path):
             Logger.err('File \"{}\" does not exist'.format(path))
             return None
@@ -102,8 +157,9 @@ class Noder:
         relpath = os.path.join(os.path.basename(storagepath),
                                os.path.relpath(path, start=storagepath))
 
+        maccess = os.path.getmtime(path)
         n = self._node(name, self.TYPE_FILE, relpath, parent,
-                       size=st.st_size, md5=md5)
+                       size=st.st_size, md5=md5, maccess=maccess)
         if self.arc:
             ext = os.path.splitext(path)[1][1:]
             if ext in self.decomp.get_format():
@@ -112,13 +168,37 @@ class Noder:
         return n
 
     def dir_node(self, name, path, parent, storagepath):
-        ''' create a new node representing a directory '''
+        '''create a new node representing a directory'''
         path = os.path.abspath(path)
         relpath = os.path.relpath(path, start=storagepath)
-        return self._node(name, self.TYPE_DIR, relpath, parent)
+        maccess = os.path.getmtime(path)
+        return self._node(name, self.TYPE_DIR, relpath,
+                          parent, maccess=maccess)
+
+    def clean_not_flagged(self, top):
+        '''remove any node not flagged and clean flags'''
+        cnt = 0
+        for node in anytree.PreOrderIter(top):
+            if node.type != self.TYPE_FILE and node.type != self.TYPE_DIR:
+                continue
+            if self._clean(node):
+                cnt += 1
+        return cnt
+
+    def flag(self, node):
+        node.flag = True
+
+    def _clean(self, node):
+        '''remove node if not flagged'''
+        if not self._has_attr(node, 'flag') or \
+                not node.flag:
+            node.parent = None
+            return True
+        del node.flag
+        return False
 
     def storage_node(self, name, path, parent, attr=None):
-        ''' create a new node representing a storage '''
+        '''create a new node representing a storage'''
         path = os.path.abspath(path)
         free = psutil.disk_usage(path).free
         total = psutil.disk_usage(path).total
@@ -127,21 +207,24 @@ class Noder:
                                total=total, parent=parent, attr=attr, ts=epoch)
 
     def archive_node(self, name, path, parent, archive):
+        '''crete a new node for archive data'''
         return anytree.AnyNode(name=name, type=self.TYPE_ARC, relpath=path,
                                parent=parent, size=0, md5=None,
                                archive=archive)
 
-    def _node(self, name, type, relpath, parent, size=None, md5=None):
-        ''' generic node creation '''
+    def _node(self, name, type, relpath, parent,
+              size=None, md5=None, maccess=None):
+        '''generic node creation'''
         return anytree.AnyNode(name=name, type=type, relpath=relpath,
-                               parent=parent, size=size, md5=md5)
+                               parent=parent, size=size,
+                               md5=md5, maccess=maccess)
 
     ###############################################################
     # printing
     ###############################################################
     def _print_node(self, node, pre='', withpath=False,
                     withdepth=False, withstorage=False):
-        ''' print a node '''
+        '''print a node'''
         if node.type == self.TYPE_TOP:
             Logger.out('{}{}'.format(pre, node.name))
         elif node.type == self.TYPE_FILE:
@@ -175,7 +258,11 @@ class Noder:
         elif node.type == self.TYPE_STORAGE:
             hf = utils.human(node.free)
             ht = utils.human(node.total)
-            name = '{} (free:{}, total:{})'.format(node.name, hf, ht)
+            dt = ''
+            if self._has_attr(node, 'ts'):
+                dt = ', date:'
+                dt += utils.epoch_to_str(node.ts)
+            name = '{} (free:{}, total:{}{})'.format(node.name, hf, ht, dt)
             Logger.storage(pre, name, node.attr)
         elif node.type == self.TYPE_ARC:
             if self.arc:
@@ -185,16 +272,22 @@ class Noder:
             # Logger.out('{}{}'.format(pre, node.name))
 
     def print_tree(self, node, style=anytree.ContRoundStyle()):
-        ''' print the tree similar to unix tool "tree" '''
+        '''print the tree similar to unix tool "tree"'''
         rend = anytree.RenderTree(node, childiter=self._sort_tree)
         for pre, fill, node in rend:
             self._print_node(node, pre=pre, withdepth=True)
 
+    def to_dot(self, node, path='tree.dot'):
+        '''export to dot for graphing'''
+        anytree.exporter.DotExporter(node).to_dotfile(path)
+        Logger.info('dot file created under \"{}\"'.format(path))
+        return 'dot {} -T png -o /tmp/tree.png'.format(path)
+
     ###############################################################
     # searching
     ###############################################################
     def find_name(self, root, key, script=False):
-        ''' find files based on their names '''
+        '''find files based on their names'''
         if self.verbose:
             Logger.info('searching for \"{}\"'.format(key))
         self.term = key
@@ -214,7 +307,7 @@ class Noder:
         return found
 
     def _find_name(self, node):
-        ''' callback for finding files '''
+        '''callback for finding files'''
         if self.term.lower() in node.name.lower():
             return True
         return False
@@ -223,7 +316,7 @@ class Noder:
     # climbing
     ###############################################################
     def walk(self, root, path, rec=False):
-        ''' walk the tree for ls based on names '''
+        '''walk the tree for ls based on names'''
         if self.verbose:
             Logger.info('walking path: \"{}\"'.format(path))
         r = anytree.resolver.Resolver('name')
@@ -248,7 +341,7 @@ class Noder:
     # tree creationg
     ###############################################################
     def _add_entry(self, name, top, resolv):
-        ''' add an entry to the tree '''
+        '''add an entry to the tree'''
         entries = name.rstrip(os.sep).split(os.sep)
         if len(entries) == 1:
             self.archive_node(name, name, top, top.name)
@@ -262,7 +355,7 @@ class Noder:
             self.archive_node(f, name, top, top.name)
 
     def list_to_tree(self, parent, names):
-        ''' convert list of files to a tree '''
+        '''convert list of files to a tree'''
         if not names:
             return
         r = anytree.resolver.Resolver('name')
@@ -274,7 +367,7 @@ class Noder:
     # diverse
     ###############################################################
     def _sort_tree(self, items):
-        ''' sorting a list of items '''
+        '''sorting a list of items'''
         return sorted(items, key=self._sort, reverse=self.sortsize)
 
     def _sort(self, x):
@@ -283,11 +376,11 @@ class Noder:
         return self._sort_fs(x)
 
     def _sort_fs(self, n):
-        ''' sorting nodes dir first and alpha '''
+        '''sorting nodes dir first and alpha'''
         return (n.type, n.name.lstrip('\.').lower())
 
     def _sort_size(self, n):
-        ''' sorting nodes by size '''
+        '''sorting nodes by size'''
         try:
             if not n.size:
                 return 0
@@ -295,37 +388,9 @@ class Noder:
         except AttributeError:
             return 0
 
-    def to_dot(self, node, path='tree.dot'):
-        ''' export to dot for graphing '''
-        anytree.exporter.DotExporter(node).to_dotfile(path)
-        Logger.info('dot file created under \"{}\"'.format(path))
-        return 'dot {} -T png -o /tmp/tree.png'.format(path)
-
     def _get_storage(self, node):
-        ''' recursively traverse up to find storage '''
+        '''recursively traverse up to find storage'''
         return node.ancestors[1]
 
-    def get_meta_node(self, top):
-        ''' return the meta node if any '''
-        try:
-            return next(filter(lambda x: x.type == self.TYPE_META,
-                        top.children))
-        except StopIteration:
-            return None
-
-    def rec_size(self, node):
-        ''' recursively traverse tree and store dir size '''
-        if self.verbose:
-            Logger.info('getting folder size recursively')
-        if node.type == self.TYPE_FILE:
-            return node.size
-        size = 0
-        for i in node.children:
-            if node.type == self.TYPE_DIR:
-                size += self.rec_size(i)
-            if node.type == self.TYPE_STORAGE:
-                self.rec_size(i)
-            else:
-                continue
-        node.size = size
-        return size
+    def _has_attr(self, node, attr):
+        return attr in node.__dict__.keys()
diff --git a/catcli/utils.py b/catcli/utils.py
index 2c1e23e..73f08dc 100644
--- a/catcli/utils.py
+++ b/catcli/utils.py
@@ -10,13 +10,14 @@ import hashlib
 import sys
 import tempfile
 import subprocess
+import datetime
 
 # local imports
 from catcli.logger import Logger
 
 
 def md5sum(path):
-    ''' calculate md5 sum of a file '''
+    '''calculate md5 sum of a file'''
     p = os.path.realpath(path)
     if not os.path.exists(p):
         Logger.err('\nunable to get md5sum on {}'.format(path))
@@ -36,7 +37,7 @@ def md5sum(path):
 
 
 def human(size):
-    ''' human readable size '''
+    '''human readable size'''
     div = 1024.
     suf = ['B', 'K', 'M', 'G', 'T', 'P']
     if size < div:
@@ -48,14 +49,21 @@ def human(size):
     return '{:.1f}{}'.format(size, suf[-1])
 
 
+def epoch_to_str(epoch):
+    '''convert epoch to string'''
+    fmt = '%Y-%m-%d %H:%M:%S'
+    t = datetime.datetime.fromtimestamp(float(epoch))
+    return t.strftime(fmt)
+
+
 def ask(question):
-    ''' ask the user what to do '''
+    '''ask the user what to do'''
     resp = input('{} [y|N] ? '.format(question))
     return resp.lower() == 'y'
 
 
 def edit(string):
-    ''' edit the information with the default EDITOR '''
+    '''edit the information with the default EDITOR'''
     string = string.encode('utf-8')
     EDITOR = os.environ.get('EDITOR', 'vim')
     with tempfile.NamedTemporaryFile(prefix='catcli', suffix='.tmp') as f:
diff --git a/catcli/walker.py b/catcli/walker.py
index 6dd880b..19e84f7 100644
--- a/catcli/walker.py
+++ b/catcli/walker.py
@@ -17,35 +17,114 @@ class Walker:
 
     MAXLINE = 80 - 15
 
-    def __init__(self, noder, nohash=False):
+    def __init__(self, noder, nohash=False, debug=False):
         self.noder = noder
         self.noder.set_hashing(not nohash)
+        self.debug = debug
 
-    def index(self, path, name, parentpath=None, parent=None, isdir=False):
-        ''' index a folder and store in tree '''
+    def index(self, path, parent, name):
+        '''index a directory and store in tree'''
+        self._debug('indexing starting at {}'.format(path))
         if not parent:
             parent = noder.dir_node(name, path, parent)
 
         cnt = 0
         for (root, dirs, files) in os.walk(path):
             for f in files:
+                self._debug('found file {} under {}'.format(f, path))
                 sub = os.path.join(root, f)
-                n = f
-                if len(n) > self.MAXLINE:
-                    n = f[:self.MAXLINE] + '...'
-                Logger.progr('indexing: {:80}'.format(n))
+                self._log(f)
+                self._debug('index file {}'.format(sub))
                 self.noder.file_node(os.path.basename(f), sub,
-                                     parent, parentpath)
+                                     parent, path)
                 cnt += 1
             for d in dirs:
+                self._debug('found dir {} under {}'.format(d, path))
                 base = os.path.basename(d)
                 sub = os.path.join(root, d)
-                dummy = self.noder.dir_node(base, sub, parent, parentpath)
-                _, cnt2 = self.index(sub, base,
-                                     parent=dummy, parentpath=parentpath)
+                self._debug('index directory {}'.format(sub))
+                dummy = self.noder.dir_node(base, sub, parent, path)
+                cnt += 1
+                _, cnt2 = self.index(sub, dummy, base)
                 cnt += cnt2
             break
-        # clean line
-        Logger.progr('{:80}'.format(' '))
-
+        self._log(None)
         return parent, cnt
+
+    def reindex(self, path, parent, top):
+        '''reindex a directory and store in tree'''
+        cnt = self._reindex(path, parent, top)
+        cnt += self.noder.clean_not_flagged(top)
+        return cnt
+
+    def _reindex(self, path, parent, top):
+        '''reindex a directory and store in tree'''
+        self._debug('reindexing starting at {}'.format(path))
+        cnt = 0
+        for (root, dirs, files) in os.walk(path):
+            for f in files:
+                self._debug('found file {} under {}'.format(f, path))
+                sub = os.path.join(root, f)
+                maccess = os.path.getmtime(sub)
+                reindex, n = self._need_reindex(parent, f, maccess)
+                if not reindex:
+                    self._debug('\tignore file {}'.format(sub))
+                    self.noder.flag(n)
+                    continue
+                self._debug('\tre-index file {}'.format(sub))
+                self._log(f)
+                n = self.noder.file_node(os.path.basename(f), sub,
+                                         parent, path)
+                self.noder.flag(n)
+                cnt += 1
+            for d in dirs:
+                self._debug('found dir {} under {}'.format(d, path))
+                base = os.path.basename(d)
+                sub = os.path.join(root, d)
+                maccess = os.path.getmtime(sub)
+                reindex, dummy = self._need_reindex(parent, base, maccess)
+                if reindex:
+                    self._debug('\tre-index directory {}'.format(sub))
+                    dummy = self.noder.dir_node(base, sub, parent, path)
+                    cnt += 1
+                self.noder.flag(dummy)
+                self._debug('reindexing deeper under {}'.format(sub))
+                cnt2 = self._reindex(sub, dummy, top)
+                cnt += cnt2
+            break
+        self._log(None)
+        return cnt
+
+    def _need_reindex(self, top, path, maccess):
+        '''test if node needs re-indexing'''
+        cnode, newer = self.noder.get_node_if_newer(top, path, maccess)
+        if not cnode:
+            self._debug('\tdoes not exist')
+            return True, cnode
+        if cnode and not newer:
+            # ignore this node
+            self._debug('\tis not newer')
+            return False, cnode
+        if cnode and newer:
+            # remove this node and re-add
+            self._debug('\tis newer')
+            self._debug('\tremoving node {}'.format(cnode))
+            cnode.parent = None
+        self._debug('\tis to be re-indexed')
+        return True, cnode
+
+    def _debug(self, string):
+        if not self.debug:
+            return
+        Logger.log(string)
+
+    def _log(self, string):
+        if self.debug:
+            return
+        if not string:
+            # clean
+            Logger.progr('{:80}'.format(' '))
+            return
+        if len(string) > self.MAXLINE:
+            string = string[:self.MAXLINE] + '...'
+        Logger.progr('indexing: {:80}'.format(string))
diff --git a/tests/helpers.py b/tests/helpers.py
index 45f0943..ae5624b 100644
--- a/tests/helpers.py
+++ b/tests/helpers.py
@@ -10,6 +10,7 @@ import string
 import random
 import tempfile
 import shutil
+import subprocess
 
 TMPSUFFIX = '.catcli'
 
@@ -35,6 +36,22 @@ def clean(path):
     else:
         os.remove(path)
 
+
+def edit_file(path, newcontent):
+    if not os.path.exists(path):
+        write_to_file(path, newcontent)
+    else:
+        write_to_file(path, newcontent)
+
+
+def unix_tree(path):
+    if not os.path.exists(path):
+        return
+    # cmd = ['tree', path]
+    cmd = ['ls', '-R', path]
+    subprocess.call(cmd)
+
+
 ############################################################
 # catcli specific
 ############################################################
@@ -82,9 +99,21 @@ def create_rnd_file(path, filename, content=None):
     if not content:
         content = get_rnd_string(100)
     fpath = os.path.join(path, filename)
-    with open(fpath, 'w') as f:
+    return write_to_file(fpath, content)
+
+
+def write_to_file(path, content):
+    with open(path, 'w') as f:
         f.write(content)
-    return fpath
+    return path
+
+
+def read_from_file(path):
+    if not os.path.exists(path):
+        return ''
+    with open(path, 'r') as f:
+        content = f.read()
+    return content
 
 
 ############################################################
diff --git a/tests/test_graph.py b/tests/test_graph.py
index 23d147c..6b3a418 100644
--- a/tests/test_graph.py
+++ b/tests/test_graph.py
@@ -6,6 +6,8 @@ Basic unittest for graph
 """
 
 import unittest
+import tempfile
+import os
 
 from catcli.catcli import *
 from catcli.noder import Noder
@@ -19,7 +21,7 @@ class TestGraph(unittest.TestCase):
     def test_graph(self):
         # init
         path = 'fake'
-        gpath = '/tmp/graph.dot'
+        gpath = tempfile.gettempdir() + os.sep + 'graph.dot'
         self.addCleanup(clean, path)
         self.addCleanup(clean, gpath)
         catalog = Catalog(path, force=True, verbose=False)
diff --git a/tests/test_index.py b/tests/test_index.py
index 973d0ef..187dd00 100644
--- a/tests/test_index.py
+++ b/tests/test_index.py
@@ -47,7 +47,7 @@ class TestIndexing(unittest.TestCase):
         # create fake args
         tmpdirname = 'tmpdir'
         args = {'<path>': dirpath, '<name>': tmpdirname,
-                '--hash': True, '--meta': 'some meta',
+                '--hash': True, '--meta': ['some meta'],
                 '--subsize': True, '--verbose': True}
 
         # index the directory
diff --git a/tests/test_update.py b/tests/test_update.py
new file mode 100644
index 0000000..85e6894
--- /dev/null
+++ b/tests/test_update.py
@@ -0,0 +1,151 @@
+"""
+author: deadc0de6 (https://github.com/deadc0de6)
+Copyright (c) 2017, deadc0de6
+
+Basic unittest for updating an index
+"""
+
+import unittest
+
+from catcli.catcli import *
+from catcli.noder import Noder
+from catcli.walker import Walker
+from catcli.catalog import Catalog
+from tests.helpers import *
+import anytree
+
+
+class TestIndexing(unittest.TestCase):
+
+    def test_index(self):
+        # init
+        workingdir = get_tempdir()
+        catalogpath = create_rnd_file(workingdir, 'catalog.json', content='')
+        self.addCleanup(clean, workingdir)
+
+        dirpath = get_tempdir()
+        self.addCleanup(clean, dirpath)
+
+        # create 3 files
+        f1 = create_rnd_file(dirpath, 'file1')
+        f2 = create_rnd_file(dirpath, 'file2')
+        f3 = create_rnd_file(dirpath, 'file3')
+
+        # create 2 directories
+        d1 = create_dir(dirpath, 'dir1')
+        d2 = create_dir(dirpath, 'dir2')
+
+        # fill directories with files
+        d1f1 = create_rnd_file(d1, 'dir1file1')
+        d1f2 = create_rnd_file(d1, 'dir1file2')
+        d2f1 = create_rnd_file(d2, 'dir2file1')
+
+        noder = Noder()
+        top = noder.new_top_node()
+        walker = Walker(noder)
+        catalog = Catalog(catalogpath, force=True, verbose=False)
+
+        # create fake args
+        tmpdirname = 'tmpdir'
+        args = {'<path>': dirpath, '<name>': tmpdirname,
+                '--hash': True, '--meta': ['some meta'],
+                '--subsize': True, '--verbose': True}
+
+        # index the directory
+        unix_tree(dirpath)
+        cmd_index(args, noder, catalog, top, debug=True)
+        self.assertTrue(os.stat(catalogpath).st_size != 0)
+
+        # print catalog
+        noder.print_tree(top)
+
+        # add some files and directories
+        new1 = create_rnd_file(d1, 'newf1')
+        new2 = create_rnd_file(dirpath, 'newf2')
+        new3 = create_dir(dirpath, 'newd3')
+        new4 = create_dir(d2, 'newd4')
+        new5 = create_rnd_file(new4, 'newf5')
+        unix_tree(dirpath)
+
+        # modify files
+        EDIT = 'edited'
+        edit_file(d1f1, EDIT)
+
+        # update storage
+        cmd_update(args, noder, catalog, top, debug=True)
+
+        # print catalog
+        # print(read_from_file(catalogpath))
+        noder.print_tree(top)
+
+        # explore the top node to find all nodes
+        self.assertTrue(len(top.children) == 1)
+        storage = top.children[0]
+        self.assertTrue(len(storage.children) == 7)
+
+        # ensures files and directories are in
+        names = [node.name for node in anytree.PreOrderIter(storage)]
+        print(names)
+        self.assertTrue(os.path.basename(f1) in names)
+        self.assertTrue(os.path.basename(f2) in names)
+        self.assertTrue(os.path.basename(f3) in names)
+        self.assertTrue(os.path.basename(d1) in names)
+        self.assertTrue(os.path.basename(d1f1) in names)
+        self.assertTrue(os.path.basename(d1f2) in names)
+        self.assertTrue(os.path.basename(d2) in names)
+        self.assertTrue(os.path.basename(d2f1) in names)
+        self.assertTrue(os.path.basename(new1) in names)
+        self.assertTrue(os.path.basename(new2) in names)
+        self.assertTrue(os.path.basename(new3) in names)
+        self.assertTrue(os.path.basename(new4) in names)
+        self.assertTrue(os.path.basename(new5) in names)
+
+        for node in storage.children:
+            if node.name == os.path.basename(d1):
+                self.assertTrue(len(node.children) == 3)
+            elif node.name == os.path.basename(d2):
+                self.assertTrue(len(node.children) == 2)
+            elif node.name == os.path.basename(new3):
+                self.assertTrue(len(node.children) == 0)
+            elif node.name == os.path.basename(new4):
+                self.assertTrue(len(node.children) == 1)
+        self.assertTrue(read_from_file(d1f1) == EDIT)
+
+        # remove some files
+        clean(d1f1)
+        clean(d2)
+        clean(new2)
+        clean(new4)
+
+        # update storage
+        cmd_update(args, noder, catalog, top, debug=True)
+
+        # ensures files and directories are (not) in
+        names = [node.name for node in anytree.PreOrderIter(storage)]
+        print(names)
+        self.assertTrue(os.path.basename(f1) in names)
+        self.assertTrue(os.path.basename(f2) in names)
+        self.assertTrue(os.path.basename(f3) in names)
+        self.assertTrue(os.path.basename(d1) in names)
+        self.assertTrue(os.path.basename(d1f1) not in names)
+        self.assertTrue(os.path.basename(d1f2) in names)
+        self.assertTrue(os.path.basename(d2) not in names)
+        self.assertTrue(os.path.basename(d2f1) not in names)
+        self.assertTrue(os.path.basename(new1) in names)
+        self.assertTrue(os.path.basename(new2) not in names)
+        self.assertTrue(os.path.basename(new3) in names)
+        self.assertTrue(os.path.basename(new4) not in names)
+        self.assertTrue(os.path.basename(new5) not in names)
+        for node in storage.children:
+            if node.name == os.path.basename(d1):
+                self.assertTrue(len(node.children) == 2)
+            elif node.name == os.path.basename(new3):
+                self.assertTrue(len(node.children) == 0)
+
+
+def main():
+    unittest.main()
+
+
+if __name__ == '__main__':
+    main()