add section to manage password

and improve rst for Access to external hard drive

source/Installation/linux_admin.rst

@@ -183,7 +183,48 @@ to know your
     uid=1000(cronos) gid=10010(cronos) groups=1001(cronos),4(adm),24(cdrom),27(sudo),48(docker),100(users), ...
 
 
-access to external hard drive
+Change password
+===============
+
+
+To change your password
+-----------------------
+
+The command to use is `passwd`
+
+.. code-block:: shell
+    passwd
+    Changing password for cronos.
+    Current password:
+    New password:
+    Retype new password:
+    passwd: password updated successfully
+
+
+To change the password of an other user
+---------------------------------------
+
+Only root/sudoer can change the password for an other user.
+
+``sudo passwd <login>``
+
+For instance cronos which is sudoer modify the password of user *zeus* (which have a local login)
+
+.. code-block:: shell
+
+    sudo passwd zeus
+    [sudo] password for cronos:
+    New password:
+    Retype new password:
+    passwd: password updated successfully
+
+.. note::
+
+    When sudo/root change the password for an other user.
+    The system does not ask for the user password.
+
+
+Access to external hard drive
 =============================
 
 All files accessible in a Unix system are arranged in one big tree, the file hierarchy, rooted at /.
@@ -199,36 +240,38 @@ These files can be spread out over several devices.
 
 The mount command serves to attach the file system found on some device to the big file tree.
 
-basics
-
-
 When you insert usbkey in your computer, xubuntu detect it and trigger a mount command
 
 Unfortunately it does not do the same for filesystem on network.
-it will be case to connect the PC to the mk1c sequencer.
-So we will have to mount manually the filesystem of the sequencer on our machine to use allow ``rampart`` to access
+It will be the case to connect the PC to the mk1c sequencer.
+So we will have to mount manually the filesystem of the sequencer on our machine to allow ``rampart`` to access
 to the data in realtime.
 
 We saw that mount include a device on the our local file system
 So we need to know
 
 - which device
-- a location where to mount the device we called mounting point
+- a location where to mount the device, we call it the *mounting point*.
   The mounting point is just a regular directory.
-- there are several filesystem formats ext4,vfat, .... so we need to specify which protocol
+- there are several filesystem formats ext4, vfat, ... . So we need to specify which protocol
 - only root can mount a new device
 
+.. code-block:: shell
 
     sudo mount -t <format> <device> <mounting point> <option>
 
-In our case the mk1c export its filesystem over network with the cifs protocol
+In our case the mk1c export its filesystem over network with the `cifs` protocol.
 
-To do only Once
+We create the mointing point (To do only Once)
+
+.. code-block:: shell
 
     sudo mkdir -p /mnt/mk1c
 
 To do each time you need to connect the Pc to the mk1c
 
+.. code-block:: shell
+
     sudo mount -t cifs //mk1c ip address/data  -ousername=<the user on mk1c>,uid=<your uid on the Pc>,gid=<your primary gid on the Pc> /mnt/mk1c
 
     $ sudo mount -t cifs //192.168.0.10/data -ousername=minit,uid=1000,gid=1000 /mnt/mk1c
@@ -237,9 +280,11 @@ To do each time you need to connect the Pc to the mk1c
     ls -l /mnt/mk1c
 
 
-Conversely, the umount command will detach it again.
+Conversely, the `umount` command will detach it again.
 
-    to deconnect the Pc from the mk1c
+To disconnect the Pc from the mk1c
+
+.. code-block:: shell
 
     sudo umount /mnt/mk1c
 
@@ -321,7 +366,6 @@ one very useful command with du is with options
     4.0K    Videos
 
 
-
 Installing package
 ==================