1 files changed, 393 insertions, 0 deletions
diff --git a/ult/ult_7/script.rst b/ult/ult_7/script.rst
new file mode 100644
index 0000000..b4cb55c
--- /dev/null
+++ b/ult/ult_7/script.rst
@@ -0,0 +1,393 @@
+.. Objectives
+.. ----------
+   
+   .. At the end of this tutorial, you will be able to:
+   
+   ..   1. Sort lines of text files
+   ..   2. Print lines matching a pattern
+   ..   3. Translate or delete characters
+   ..   4. Omit repeated lines
+
+
+.. Prerequisites
+.. -------------
+
+..   1. Getting started with Linux
+..   2. Redirection and Piping
+
+
+ 
+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 'Text Processing'.
+
+.. L2
+
+{{{ Show slide with objectives }}} 
+
+.. R2
+
+At the end of this tutorial, you will be able to,
+
+ 1. Sort lines of text files
+ #. Print lines matching a pattern
+ #. Translate or delete characters
+ #. Omit repeated lines.
+
+
+.. L3
+
+{{{ Switch to the pre-requisite slide }}}
+
+.. R3
+
+Before beginning this tutorial,we would suggest you to complete the 
+former tutorials as being displayed currently.
+
+.. R4
+
+In this tutorial, we shall learn about text processing.
+TO begin with, consider data kept in two files, namely marks1.txt and 
+students.txt
+Let us see what data they contain. Open a terminal and type, 
+
+.. L4
+
+{{{ Open the terminal }}}
+::
+
+    cat marks1.txt
+    cat students.txt
+
+.. R5
+
+Let's say we wish to sort the output in the alphabetical order
+of the names of the files. We can use the ``sort`` command for this
+purpose.
+
+We just pipe the previous output to the ``sort`` command as,
+
+.. L5
+::
+
+    cut -d " " -f 2- marks1.txt | paste -d " " students.txt -| sort
+
+.. R6
+
+Let's say we wish to sort the names, based on the marks in the first
+subject i.e. the first column after the name. ``sort`` command also allows us to
+specify the delimiter between the fields and sort the data on a particular
+field. ``-t`` option is used to specify the delimiter and ``-k`` option
+is used to specify the field. 
+
+.. L6
+::
+
+    cut -d " " -f 2- marks1.txt | paste -d " " students.txt -| sort -t " " -k 2
+
+.. L7
+
+{{{ Show slide with, Sort... }}}
+
+.. R7
+
+This command give us a sorted output as required. But, what if we would 
+like the output to appear in the reverse order. ``-r`` option allows the output
+to be sorted in the reverse order and the ``-n`` option is used to choose 
+a numerical sorting. 
+
+.. R8
+
+Let us do it on the terminal and see for ourselves, 
+
+.. L8
+
+{{{ Switch to the terminal }}}
+::
+
+    cut -d " " -f 2- marks1.txt | paste -d " " students.txt -| 
+    sort -t " " -k 2 -rn
+
+.. R9
+
+Suppose, While you are compiling the student marklist, Anne walks up to you and
+wants to know her marks. You, being a kind person that you are, oblige.
+But you do not wish to her to see the marks that others have scored. What
+do you do? Here, the ``grep`` command comes to your rescue. 
+
+``grep`` is a command line text search utility. You can use it to search
+for Anne and show her, what she scored. ``grep`` allows us to search for a
+search string in files. But we could, like any other command, pipe the
+output of other commands to it. So, we shall use the previous combination
+of cut and paste that we had, to get the marks of students along with their
+names and search for Anne in that. 
+
+.. L9
+::
+
+    cut -d " " -f 2- marks1.txt | paste -d " " students.txt - | grep Anne 
+
+.. R10
+
+This will give us only the line containing the word Anne as the output.
+The grep command is by default case-sensitive. So, we wouldn't have got
+the result if we had searched for anne, with a small a, instead of 
+Anne, with a capital a. But, what if we didn't know, whether the name was 
+capitalized or not? ``grep`` allows you to do case-insensitive searches 
+by using the ``-i`` option. 
+
+.. L10
+::
+
+    cut -d " " -f 2- marks1.txt | paste -d " " students.txt - | grep -i Anne 
+
+.. R11
+
+Now, in another scenario, if we wished to print all the lines, which do
+not contain the word Anne, we could use the ``-v`` option. 
+
+.. L11
+::
+
+    cut -d " " -f 2- marks1.txt | paste -d " " students.txt - | grep -iv Anne
+
+.. R12
+
+grep allows us to do more complex searches, for instance, searching for
+sentences starting or ending with a particular pattern and regular
+expression based searches. 
+
+{{{ Show slide with, tr }}}
+
+``tr`` is a command that takes two sets of characters as parameters, and
+replaces occurrences of the characters in the first set with the
+corresponding elements from the other set. It reads from the standard
+output and writes to the standard output. 
+
+For instance, if we wish to replace all the lower case letters in the
+students file with upper case, we can do it as, 
+
+.. L12
+
+{{{ Switch to the terminal }}}
+::
+
+    cat students.txt | tr a-z A-Z
+
+.. R13
+
+A common task is to remove empty newlines from a file. The ``-s`` flag
+causes ``tr`` to compress sequences of identical adjacent characters in its
+output to a single token. For example,
+
+.. L13
+::
+
+    tr -s '\n' '\n'
+
+.. R14
+
+Hit enter 2-3 times and see that every time we hit enter we get a newline.
+
+.. L14
+::
+
+    <Enter>
+    <Enter> 
+
+.. R15
+
+It replaces sequences of one or more newline characters with a single newline.
+
+The ``-d`` flag causes ``tr`` to delete all tokens of the specified set of
+characters from its input. In this case, only a single character set
+argument is used. The following command removes carriage return characters,
+thereby converting a file in DOS/Windows format to the Unix format. 
+
+.. L15
+::
+
+    cat foo.txt | tr -d '\r' > bar.txt
+
+.. R16
+
+The ``-c`` flag complements the first set of characters.
+
+.. L16
+::
+
+    tr -cd '[:alnum:]' 
+
+.. R17
+
+It therefore removes all non-alphanumeric characters.
+
+Let us consider one more scenario.Suppose we have a list of items, say books, 
+and we wish to obtain a list which names of all the books only once, without 
+any duplicates. To achieve this, we use the ``uniq`` command. Let us first 
+have a look at our file
+
+.. L17
+::
+
+    cat items.txt
+
+.. R18
+
+Now, let us try and get rid of the duplicate lines from this file using 
+the ``uniq`` command.
+
+.. L18
+::
+
+    uniq items.txt
+
+.. R19
+
+Nothing happens! Why? The ``uniq`` command removes duplicate lines only when 
+they are next to each other. So, henceforth, we get a sorted file from the 
+original file and work with that file. 
+
+.. L19
+::
+
+    sort items.txt | uniq
+
+.. R20
+
+``uniq -u`` command gives the lines which are unique and do not have any 
+duplicates in the file. ``uniq -d`` outputs only those lines which 
+have duplicates. 
+
+.. L20 
+::
+
+    uniq -u items-sorted.txt 
+
+.. R21
+
+The ``-c`` option displays the number of times each line occurs in the file.
+
+.. L21
+::
+
+    uniq -dc items-sorted.txt
+
+.. L22
+
+{{{ Show summary slide }}}
+
+.. R22
+
+This brings us to the end of the end of this tutorial.
+In this tutorial, we have learnt to, 
+ 
+  1. Use the ``sort`` command to sort lines of text files.
+  #. Use the ``grep`` command to search text pattern.
+  #. Use the ``tr`` command to translate and/or delete characters.
+  #. Use the ``uniq`` command to omit repeated lines in a text. 
+
+.. L23
+
+{{{ Show self assessment questions slide }}}
+
+.. R23
+
+Here are some self assessment questions for you to solve
+
+1. To obtain patterns; one per line, which of the following command is used ?
+   
+    - grep -f
+    - grep -i
+    - grep -v
+    - grep -e
+
+2. Translate the word 'linux' to upper-case.
+
+3. Sort the output of the ``ls -al`` command.
+
+.. L24
+
+{{{ Solution of self assessment questions on slide }}}
+
+.. R24
+
+And the answers,
+
+1. In order to obtain patterns one per line, we use the ``grep`` command
+    alongwith the -f option.
+
+2. We use the tr command to change the word into uppercase 
+::
+
+    echo 'linux' | tr a-z A-Z
+ 
+
+3. We use the sort command as, 
+::
+     
+    ls -al | sort -n -k5
+The -n  means "sort numerically", and the -k5 option means to key off of 
+column five. 
+
+.. L25
+
+{{{ Show the SDES & FOSSEE slide }}}
+
+.. R25
+
+Software Development techniques for Engineers and Scientists - SDES, is an 
+initiative by FOSSEE. For more information, please visit the given link.
+
+Free and Open-source Software for Science and Engineering Education - FOSSEE, is
+based at IIT Bombay which is funded by MHRD as part of National Mission on 
+Education through ICT.
+
+.. L26
+
+{{{ Show the ``About the Spoken Tutorial Project'' slide }}}
+
+.. R26
+
+Watch the video available at the following link. It summarises the Spoken 
+Tutorial project.If you do not have good bandwidth, you can download and 
+watch it. 
+
+.. L27
+
+{{{ Show the `` Spoken Tutorial Workshops'' slide }}}
+
+.. R27
+
+The Spoken Tutorial Project Team conducts workshops using spoken tutorials,
+gives certificates to those who pass an online test.
+
+For more details, contact contact@spoken-tutorial.org
+
+.. L28
+
+{{{ Show the ``Acknowledgements'' slide }}}
+
+.. R28
+
+Spoken Tutorial Project is a part of the "Talk to a Teacher" project.
+It is supported by the National Mission on Education through ICT, MHRD, 
+Government of India. More information on this mission is available at the 
+given link.
+
+.. L29
+
+{{{ Show the Thank you slide }}}
+
+.. R29
+
+Hope you have enjoyed this tutorial and found it useful.
+Thank you!