1 files changed, 492 insertions, 0 deletions
diff --git a/ult/ult_2/script.rst b/ult/ult_2/script.rst
new file mode 100644
index 0000000..21db359
--- /dev/null
+++ b/ult/ult_2/script.rst
@@ -0,0 +1,492 @@
+.. Objectives
+.. ----------
+   
+   .. At the end of this tutorial, you will be able to:
+   
+   ..   1. Copy files from one location to another.
+   ..   2. Remove files and directories.
+   ..   3. Change permissions and ownership of files.
+   ..   4. Navigate through directories and files.
+
+.. Prerequisites
+.. -------------
+
+..   1. Using Linux tools - Part 1
+
+ 
+Script
+------
+
+.. L1
+
+{{{ Show the  first slide containing title, name of the production
+team along with the logo of MHRD }}}
+
+.. R1
+
+Hello friends and Welcome to the tutorial on 
+'Using linux tools - Part 2'.
+
+.. L2
+
+{{{ Show slide with objectives }}} 
+
+.. R2
+
+At the end of this tutorial, you will be able to,
+
+ 1. Copy files from one location to another.
+ #. Remove files and directories.
+ #. Change permissions and ownership of files.
+ #. Navigate through directories and files.
+
+.. L3
+
+{{{ Switch to the pre-requisite slide }}}
+
+.. R3
+
+Before beginning this tutorial,we would suggest you to complete the 
+tutorial on "Using Linux tools - Part 1".
+
+.. R4
+
+Let us start with the concept of basic file handling.
+Let's begin with removing files.
+The ``rm`` command  is used to delete files. 
+
+Here's example to remove a file named "foo" from the directory "sdes", 
+
+.. L4
+
+{{{ Navigate to /home/user/sdes/ }}}
+::
+
+    rm foo
+    ls
+
+.. R5
+
+Note that, as such, ``rm`` works only for files and not for directories.
+For instance, if you try to remove a directory named ``bar`` using, 
+
+.. L5
+::
+
+    rm bar
+
+.. R6
+
+we get an error saying, cannot remove `bar`: Is a directory. But ``rm``
+takes additional arguments which can be used to remove a directory and all
+of it's content, including sub-directories.We use the ``-r`` option. 
+
+.. L6
+::
+
+    rm -r bar
+    ls
+
+.. R7
+
+It removes the directory ``bar`` and all of it's content including
+sub-directories, recursively. The ``-r`` stands for recursive. 
+
+Let's say we wish to copy a file, ``foo`` from ``sdes/linux-tools/scripts``, 
+which is the source location to the target location ``sees/linux-tools``, 
+how would we do it? 
+
+.. L7
+::
+
+    pwd 
+    cp linux-tools/scripts/foo linux-tools/
+
+.. R8
+
+Note, that we haven't changed the name of the file name at the target
+location. We could have done that by specifying a new filename at the
+target location,as,
+
+.. L8
+::
+
+    cp linux-tools/scripts/foo linux-tools/bar
+
+.. R9
+
+This copies the file ``foo`` to the new location, but with the new name,
+``bar``. 
+
+But, what would have happened if we had a file named ``bar`` already at the
+new location? Let's try doing the copy again, and see what happens. 
+
+.. L9
+::
+
+    cp linux-tools/scripts/foo linux-tools/bar
+
+.. R10
+
+We get no error message, what happened? ``cp`` actually overwrites files.
+In this case, it's not a problem since, we just re-copied the same content,
+but in general it could be a problem, and we could lose data. To prevent
+this, we use the ``-i`` flag with ``cp``. 
+
+.. L10
+::
+
+    cp -i linux-tools/scripts/foo linux-tools/bar
+
+.. R11
+
+We are now prompted, whether the file should be over-written. To over-write
+say ``y``, else say ``n``. 
+
+Now, let's try to copy the directory ``sdes`` to a new directory called
+``course``. How do we do it?
+
+.. L11
+::
+
+    cd /home/user
+    cp -i sdes course
+   
+.. R12
+
+``cp`` refuses to copy the directory ``sdes``. We use the option ``-r``
+(recursive) to copy the directory and all it's content. 
+
+.. L12
+::
+
+    cd /home/user
+    cp -ir sdes course
+    ls
+
+.. R13
+
+We see that a new directory named course has been created with all it's 
+contents.
+
+Now, If we want to move files, instead of copying them, one way to go about
+it, would be to ``cp`` the file to the new location and ``rm`` the old
+file. Instead, you can make use of only one command which can do this task at 
+one go. The ``mv`` command can move files or directories. It also takes 
+the ``-i`` option to prompt before overwriting. 
+
+.. L14
+::
+
+    cd /home/user
+    mv -i sdes/ course/
+
+.. R15
+
+Let us understand what exactly happened when we used the ``mv`` command
+
+.. L15
+::
+
+    ls course
+
+.. R16
+
+We can see that the ``sdes`` directory has been inserted as sub-directory
+of the ``course`` directory. The move command doesn't over-write
+directories, but the ``-i`` option is useful when moving files around.
+
+A common way to rename files (or directories), is to copy a file (or a
+directory) to the same location, with a new name. 
+
+.. L16
+::
+
+    mv sdes/linux-tools sdes/linux
+
+.. R17
+
+It renames the ``linux-tools`` directory to just ``linux``
+
+While moving around our files and directories, we have been careful to stay
+within the ``/home/`` directory, but other than that there are many other 
+directories too. Let us take this opportunity to understand a few things 
+about the linux file hierarchy and file permissions. 
+
+.. L17
+::
+
+    cd /
+
+{{{ Switch to slide, Linux File Hierarchy }}}
+
+.. R18
+
+The ``/`` directory is called the root directory. All the files and
+directories, (even if they are on different physical devices) appear as
+sub-directories of the root directory. 
+
+.. L18
+
+{{{ Switch to terminal }}}
+::
+
+    ls 
+
+.. R19
+
+You can see the various directories present at the top most level.
+
+.. L19
+
+{{{ Pause for sometime and then continue }}}
+
+.. R20
+
+For more information, it is recommended that you look at the ``man`` page
+of ``hier``. 
+
+.. L20
+::
+
+    man hier
+
+{{{ Pause for sometime and then hit q }}}
+
+.. R21
+
+Let us now look at file permissions. Linux is a multi-user environment and
+allows users to set permissions to their files to allow only a set of
+people to read or write it. Similarly, it is not "safe" to allow system
+files to be edited by any user. All this access control is possible in
+Linux. 
+
+To start, in the root directory, say,
+
+.. L21
+::
+
+    ls -l
+
+.. R22
+
+You again get a list of all the sub-directories, but this time with a lot
+of additional information. Let us try and understand what this output says
+Consider the first line of the output,
+
+.. L22
+
+{{{ Highlight the required portions accordingly while narrating }}}
+
+.. R23
+
+The first column denotes the type and the access permissions of the file.
+The second is the number of links. The third and fourth are the owner and
+group of the file. The next field is the size of the file in bytes. The
+next field is the date and time of modification and the last column is the
+file name.
+We shall look at the permissions of the file now, ie., the first column of
+the output. 
+
+The first character in the first column specifies, whether the item is a
+file or a directory. Files have a ``-`` as the first character and
+directories have a ``d``. 
+
+The next 9 characters define the access permissions of the file. Before
+looking at it, we need to briefly study groups and users and ownership. 
+
+We already know what the first character in the first column (in the output
+of ``ls -l``) is for. The rest of the 9 characters are actually sets of 3
+characters of each. The first set of 3 characters defines the permissions
+of the user, the next 3 is for the group and the last three is for others.
+Based on the values of these characters, access is provided or denied to
+files, to each of the users. 
+
+So, what does each of the three characters stand for? Let's suppose we are
+looking at the set, corresponding to the permissions of the user. In the
+three characters, the first character can either be an ``r`` or a ``-``.
+Which means, the user can either have the permissions to read the file or
+not. If the character is ``r``, then the user has the permissions to read
+the file, else not. Similarly, ``w`` stands for write permissions and
+decides whether the user is allowed to write to the file. ``x`` stands for
+execute permissions. You cannot execute a file, if you do not have the
+permissions to execute it.
+
+Similarly, the next set of characters decides the same permissions for the
+members of the group, that the file is associated with. The last set of
+characters defines these permissions for the users, who are neither owners
+of the file nor in the group, with which the file is associated. 
+
+Now, it's not as if these permissions cannot be changed. If you are the
+owner of a file, you can change the permissions of a file, using the
+``chmod`` command.
+
+.. L23
+
+.. R24
+
+Let's say, we wish to give the execute permissions for a file, to both the
+user and the group, how do we go about doing it? To be more explicit, given
+a file ``foo.sh``, with the permissions flags as ``-rw-r--r--``, change it
+to ``-rwxr-xr--``. 
+
+The following command does it for us, 
+
+.. L24
+::
+
+    chmod ug+x foo.sh
+    ls -l foo.sh
+
+.. R25
+
+As you can see, the permissions have been set to the required value. But
+what did we exactly do? Let us try and understand. 
+
+.. L25
+
+{{{ Switch to slide,Symbolic modes }}}
+
+.. R26
+
+In the command, the parameter ``ug+x`` is the mode parameter to the
+``chmod`` command. It specifies the changes that need to be made to the
+permissions of the file ``foo.sh``. 
+The ``u`` and ``g`` stand for the user and group, respectively. The ``x``
+stands for the execute permission and ``+`` stands for adding the
+specified permission. So, essentially, we are asking ``chmod`` command to
+add the execute permission for the user and group. The permission of others
+will remain unchanged. 
+
+So, if we wished to add the execute permission to all the users, instead of
+adding it to just the user and group, we would have instead said 
+
+.. L26
+::
+
+    chmod a+x foo.sh 
+
+.. R27
+
+or 
+
+.. L27
+::
+
+    chmod ugo+x foo.sh
+
+.. R28
+
+Pause the video here, try out the following exercise and resume the video.
+
+.. L28
+
+.. L29
+
+{{{ Show slide with exercise 1 }}}
+
+.. R29
+
+Change the permissions of a directory along with all of its
+sub-directories and files.
+
+.. L30
+
+{{{ Show slide with solution 1 }}}
+
+.. R30
+
+To change the permissions of a directory along with all of its
+sub-directories and files, recursively, we use the ``-R`` option
+with the chmod command as shown
+
+  chmod go-r -R <directory name>/
+
+.. R31
+
+It is important to note that the permissions of a file can only be changed
+by a user who is the owner of a file or the superuser.
+
+What if we wish to change the ownership of a file? The ``chown`` command is
+used to change the owner and group. 
+By default, the owner of a file (or directory) is the user that
+created it. The group is a set of users that share the same access
+permissions i.e., read, write and execute. 
+For instance, to change the user and the group of the file
+``wonderland.txt`` to ``alice`` and ``users``, respectively, we say.
+
+.. L31
+::
+
+    chown fossee:users wonderland.txt
+
+.. R32
+
+We get an error saying, the operation is not permitted.
+We have attempted to change the ownership of a file that we own, to a
+different user. Logically, this shouldn't be possible, because, this can
+lead to problems, in a multi-user system. 
+Only the superuser is allowed to change the ownership of a file from one
+user to another. The superuser or the ``root`` user is the only user
+empowered to a certain set of tasks and hence is called the superuser. The
+command above would have worked, if you did login as the superuser and
+then changed the ownership of the file. 
+
+.. L32
+
+.. L33
+
+{{{ Show summary slide }}}
+
+.. R33
+
+This brings us to the end of the tutorial.In this tutorial, we have learnt to,
+
+ 1. Copy and move files from one location to another, using the ``cp`` 
+    and ``mv`` commands respectively.
+ #. Remove files using ``rm`` command. 
+ #. Understand the Linux file hierarchy.
+ #. Change permissions and ownership of files, using the ``chmod`` 
+    and ``chown`` commands respectively.
+
+.. L34
+
+{{{ Show self assessment questions slide }}}
+
+.. R34
+
+Here are some self assessment questions for you to solve
+
+1. How to copy all the contents of one folder into another?
+
+2. How will you rename the file wonderland.txt to alice.txt using the 
+   commands learnt so far?
+
+.. L35
+
+{{{ Solution of self assessment questions on slide }}}
+
+.. R35
+
+And the answers,
+
+1. We use the ``cp`` command along with a star sign. The star denotes that 
+   it will copy all the files of folder 1 to folder 2.
+::
+
+    cp folder1/* folder2 
+
+2. To rename a file, we use the ``mv`` command as,
+::
+
+    mv wonderland.txt alice.txt
+
+.. L36
+
+{{{ Show the Thankyou slide }}}
+
+.. R36
+
+Hope you have enjoyed this tutorial and found it useful.
+Thank you!
+