fix rst syntax in file_system

source/Unix/file_system.rst

@@ -37,7 +37,7 @@ do you already know a tree structure in biology?
   :width: 500px
 
 file system tree structure
-=========================
+==========================
 
 .. figure:: ../_static/unix/images/UnixDirectoryTree.png
       :class: align-center
@@ -272,20 +272,20 @@ mv warning
    
 The **mv** command has not the same effect depending if src and dest are directories or files.
    
-+--------------+-----------+------------------------------------------------------------+
-| src type     | dest type | action                                                     |
-+==============+===========+============================================================+
++--------------+-----------+------------------------------------------------------------=+
+| src type     | dest type | action                                                      |
++==============+===========+=============================================================+
 | one file     | file      | the src file is renamed into dest file                      |
-|              |           | beware if dest file already exists it's lost               |
-+--------------+-----------+------------------------------------------------------------+
+|              |           | beware if dest file already exists it's lost                |
++--------------+-----------+-------------------------------------------------------------+
 | several file | file      | all src files are lost only the last one is renamed as dest |
-+--------------+-----------+------------------------------------------------------------+
-| file         | dir       | all src files are moved in dest directory                  |
-|              |           | dest directory must exists. If not it is consider as a file  |
-+--------------+-----------+------------------------------------------------------------+
-| dir          | dir       | all src directories are moved in dest directory            |
-|              |           | the dest directory must already exists                     |
-+--------------+-----------+------------------------------------------------------------+
++--------------+-----------+-------------------------------------------------------------+
+| file         | dir       | all src files are moved in dest directory                   |
+|              |           | dest directory must exists. If not it is consider as a file |
++--------------+-----------+-------------------------------------------------------------+
+| dir          | dir       | all src directories are moved in dest directory             |
+|              |           | the dest directory must already exists                      |
++--------------+-----------+-------------------------------------------------------------+
 
 Exercise:
 ---------