diff --git a/persoconf/commands/check.py b/persoconf/commands/check.py
new file mode 100644
index 0000000..5c70431
--- /dev/null
+++ b/persoconf/commands/check.py
@@ -0,0 +1,154 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+           
+import os.path
+import filecmp
+
+# --------------------------------------
+def init(parser):
+    """Initialize check subcommand"""
+
+    parser.add_argument( "app"                                                ,
+                         type=str                                             ,
+                         nargs="?"                                            ,
+                         help="The app to check" )
+
+    parser.add_argument( "files"                                              ,
+                         type=str                                             ,
+                         nargs="*"                                            ,
+                         default=[]                                           ,
+                         help="The files to check ; default to all "          \
+                              "added files" )
+    
+    parser.add_argument( "-d", "--diff"                                       ,
+                         type=str                                             ,
+                         help="Print the diff between the saved and the new " \
+                              "file/directory" )
+
+
+# --------------------------------------
+def run(args, persoconf, logger):
+
+    logger.debug("Starting 'check' command")
+
+    # app == None => check all apps
+    apps_to_check = {}
+    if args.app is None:
+        apps_to_check = persoconf.list_apps(logger=logger)
+
+    else:
+        try:
+            appmeta = Metafile(
+                                json_path = os.path.join( persoconf.path,
+                                                          args.app,
+                                                          persoconf.metafile )
+                              )
+
+            apps_to_check[appmeta.name] = appmeta
+
+        except FileNotFoundError:
+            logger.error( "Metafile %s does not exist for app %s"
+                          % (persoconf.metafile, args.app) )
+            exit(1)
+
+        except MalformedMetafileError:
+            logger.error( "Malformed metafile %s in app %s"
+                           % (persoconf.metafile, args.app) )
+            exit(1)
+
+
+    for app in apps_to_check:
+
+        logger.info( "App %s:" % app )
+
+        if args.files != []:
+
+            dstdic = apps_to_check[app].get_files_dst2src() # Get that here
+                                                            # for optimization
+
+            # The filenames can be confnames or real files names. For each
+            # we'll assume first that it's a confname, then that it's a file
+            # name if that fails.
+            for f in args.files:
+
+                # 1) It's probably a confname
+                if f in apps_to_check[app].files:
+
+                    persoconf_backup_path = os.path.join( persoconf.path,
+                                                          app,
+                                                          f )
+
+                    original_file_path = apps_to_check[app].files[f]["dest"]
+
+                    _compare_and_log( original_file_path,
+                                      persoconf_backup_path,
+                                      logger )
+
+                # 2) If not, it must be a real filename
+                else:
+
+                    absf = contractuser(os.path.abspath(os.path.expanduser(f)))
+                    if absf in dstdic:
+
+
+                        persoconf_backup_path = os.path.join( persoconf.path,
+                                                              app,
+                                                              dstdic[absf]  )
+
+                        original_file_path = absf
+
+                        _compare_and_log( original_file_path,
+                                          persoconf_backup_path,
+                                          logger )
+
+
+                    # 3) Otherwise, no idea what it is
+                    else:
+                        logger.warning( "Cannot find file %s in app data; "   \
+                                        "ignoring it"
+                                        % f )
+                        continue
+
+        # If they were no 'file' args, it means we need to update all files in
+        # the app
+        else:
+
+            for f in apps_to_check[app].files:
+
+                persoconf_backup_path = os.path.join( persoconf.path,
+                                                      app,
+                                                      f )
+
+                original_file_path = apps_to_check[app].files[f]["dest"]
+
+                _compare_and_log( original_file_path,
+                                  persoconf_backup_path,
+                                  logger )
+
+
+# --------------------------------------
+def _compare_and_log(original_file_path, persoconf_backup_path, logger):
+    """Compare a file with its persoconf backup and log the result (at info
+       level if the files are matching, warning level if they are not)."""
+    
+    resolved_ofp = os.path.expanduser(original_file_path)
+    resolved_pbp = os.path.expanduser(persoconf_backup_path)
+
+    is_dir = os.path.isdir( resolved_ofp )
+
+    if filecmp.cmp(resolved_ofp, resolved_pbp) :
+        if is_dir:
+            logger.info( "No modification on %s/"
+                         % original_file_path )
+        else:
+            logger.info( "No modification on %s"
+                         % original_file_path )
+
+    else:
+        if is_dir:
+            logger.warning( "Dir %s/ was modified"
+                            % original_file_path )
+        else:
+            logger.warning( "File %s was modified"
+                            % original_file_path )
+
diff --git a/persoconf/main.py b/persoconf/main.py
index f2b2f64..5b07637 100755
--- a/persoconf/main.py
+++ b/persoconf/main.py
@@ -16,7 +16,7 @@ from persoconf import Persoconf, FileInsteadOfDirError, \
                       PersoconfRootDoesNotExistError
 
 import commands.list,   commands.package, commands.update, commands.add, \
-       commands.delete
+       commands.delete, commands.check
 
     
 
@@ -71,6 +71,12 @@ parser_add = subparsers.add_parser( "add"                                     ,
                                          "to an existing app" )
 commands.add.init(parser_add)
 
+# Check
+parser_check = subparsers.add_parser( "check"                                 ,
+                                      help="Checks if the backuped and the "  \
+                                           "original file are different." )
+commands.check.init(parser_check)
+
 # Delete
 parser_del = subparsers.add_parser( "delete"                                  ,
                                     help="Delete an app from the persoconf "  \
@@ -159,6 +165,11 @@ if args.command == "delete":
 if args.command == "add":
     commands.add.run(args, persoconf, log)
 
+# CHECK COMMAND
+########################################
+if args.command == "check":
+    commands.check.run(args, persoconf, log)
+
 # UPDATE COMMAND
 ########################################
 if args.command == "update":