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Diffstat (limited to 'ult/ult_4')
| -rw-r--r-- | ult/ult_4/marks.txt | 5 | ||||
| -rw-r--r-- | ult/ult_4/marks1.txt | 5 | ||||
| -rw-r--r-- | ult/ult_4/script.rst | 384 | ||||
| -rw-r--r-- | ult/ult_4/students.txt | 5 | ||||
| -rw-r--r-- | ult/ult_4/ult4.tex | 234 |
5 files changed, 633 insertions, 0 deletions
diff --git a/ult/ult_4/marks.txt b/ult/ult_4/marks.txt new file mode 100644 index 0000000..f97b743 --- /dev/null +++ b/ult/ult_4/marks.txt @@ -0,0 +1,5 @@ +89 92 85 +98 47 67 +67 82 76 +78 97 60 +67 68 69 diff --git a/ult/ult_4/marks1.txt b/ult/ult_4/marks1.txt new file mode 100644 index 0000000..9a5299d --- /dev/null +++ b/ult/ult_4/marks1.txt @@ -0,0 +1,5 @@ +5 89 92 85 +4 98 47 67 +1 67 82 76 +2 78 97 60 +3 67 68 69 diff --git a/ult/ult_4/script.rst b/ult/ult_4/script.rst new file mode 100644 index 0000000..cd3168a --- /dev/null +++ b/ult/ult_4/script.rst @@ -0,0 +1,384 @@ +.. Objectives +.. ---------- + + .. At the end of this tutorial, you will be able to: + + .. 1. Understand what is Redirection and Piping. + .. 2. Learn various features of shell. + +.. Prerequisites +.. ------------- + +.. 1. Using Linux tools - Part 1 +.. 2. Using Linux tools - Part 2 +.. 3. Using Linux tools - Part 3 + +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 4'. + +.. L2 + +{{{ Show slide with objectives }}} + +.. R2 + +At the end of this tutorial, you will be able to, + + 1. Understand what is Redirection and Piping. + #. Learn various features of the shell. + +.. L3 + +{{{ Switch to the pre-requisite slide }}} + +.. R3 + +Before beginning this tutorial,we would suggest you to complete the +tutorial on "Using Linux tools from Part 1 to Part 3". + +.. R4 + +Let us begin with the concept of 'Redirection and Piping' which can do the +same operations as the ``cut`` and ``paste`` commands. + +Consider the files ``marks.txt`` and ``students.txt``, which has the +following contents + +.. L4 + +{{{ Open the terminal }}} +:: + + cat marks1.txt + cat students.txt + +.. R5 + +Let us view the contents of both the files side-by-side + +.. L5 +:: + + cut -d " " -f 2- marks1.txt | paste -d " " students.txt - + +.. R6 + +Now, in order to view the same ouput in a file at a new location, we say, + +.. L6 +:: + + cut -d " " -f 2- marks1.txt > /tmp/m_tmp.txt + paste -d " " students.txt m_tmp.txt + +.. R7 + +Let's first try to understand the second solution, which is a two step +solution. Later, we shall look at the first solution. + +.. L7 + +.. L8 + +{{{ Show slide, with Redirection }}} + +.. R8 + +The standard output, in general, goes to the display. +Hence, the output of the commands that we type, come out to the display. +This may not always be what we require. + +For instance, in the solution above, we use the cut command and get only +the required columns of the file and write the output to a new temporary +file. The ``>`` character is used to state that we wish to redirect the +output, and it is followed by the location to which we wish to redirect. +For example, + + command > file1 + +.. L9 + +{{{ Show slide, with Redirection... }}} + +.. R9 + +Similarly, the standard input (stdin) can be redirected as, + + command < file1 + +The input and the output redirection could be combined in a single command, as, + + command < infile > outfile + +There is actually a third kind of standard stream, called the Standard +error (stderr). Any error messages that you get, are coming through this +stream. Like ``stdout``, ``stderr`` also streams to the display by default, +but it could be redirected to a file, as well. + +.. R10 + +For instance, let's introduce an error into the ``cut`` command used +before. We change the ``-f`` option to ``-c`` + +.. L10 + +{{{ Switch to terminal }}} +:: + + cut -d " " -c 2- marks1.txt > /tmp/m_tmp.txt + +.. R11 + +This prints an error that says the delimiter option should be used with the +fields option only, and you can verify that the ``m_tmp.txt`` file is +empty. We can now, redirect the ``stderr`` also to a file, instead of +showing it on the display. + +.. L11 +:: + + cut -d " " -f 2- marks1.txt 1> /tmp/m_tmp.txt 2> /tmp/m_err.txt + +.. R12 + +The above command redirects all the errors to the ``m_err.txt`` file +and the output to ``m_tmp.txt`` file. When redirecting, 1 stands +for ``stdout`` and 2 stands for ``stderr``. + +Let us complete the solution by using the ``paste`` command + +.. L12 +:: + + paste -d " " students.txt m_tmp.txt + +.. R13 + +So, in two steps we solved the problem of getting rid of the roll numbers +from the marks file and displaying the marks along with the names of the +students. Now, that we know how to redirect output, we could choose to +write the output to a file, instead of showing on the display. + +Let us now look at the first solution. + +.. L13 +:: + + cut -d " " -f 2- marks1.txt | paste -d " " students.txt - + +.. L14 + +{{{ Show slide, with Piping }}} + +.. R14 + +First of all, the hyphen at the end is to ask the paste command to read the +standard input, instead of looking for a FILE. The ``man`` page of ``paste`` +command gives us this information. + +The character ``|`` is called a pipe. +Now, what is happening with the ``cut`` command. If we look at the command only +up to the ``|`` character, it is a normal ``cut`` command . So, the ``|`` seems +to be joining the commands in some way. +Essentially, what we are doing is, to redirect the output of the first +command to ``stdin`` and the second command takes input from the ``stdin``. + +More generally, + + command1 | command2 + +executes ``command1`` and sends it's output to the ``stdin``, which is then +used as the input for ``command2``. This activity is commonly called piping. + +.. L15 + +{{{ Show slide, with Piping... }}} + +.. R15 + +This is roughly equivalent to using two redirects and a temporary file + + command1 > tempfile + command2 < tempfile + rm tempfile + +Also, given that a pipe is just a way to send the output of the command to +the ``stdin``, it should be obvious, to you that we can use a chain of +pipes. Any number of commands can be piped together and you need not be +restricted to two commands. + +The Bash shell has some nice features, that make our job of using the shell +easier and much more pleasant. We shall look at a few of them, here. + +Bash provides the feature of tab completion. What does tab completion mean? +When you are trying to type a word and you have entered enough portion of the +word, bash can complete the word for you, by hitting the tab key. + +If on hitting the tab key, the word doesn't get completed, either the word +doesn't exist or the word cannot be decided unambiguously. If the case is +the latter one, hitting the tab key a second time, will list the +possibilities. + +.. L16 + +{{{ Show slide, with Tab-completion }}} + +.. R16 + +Bash provides tab completion for the following. + + 1. File Names + 2. Directory Names + 3. Executable Names + 4. User Names (when they are prefixed with a ~) + 5. Host Names (when they are prefixed with a @) + 6. Variable Names (when they are prefixed with a $) + +.. R17 + +For example, + +.. L17 + +{{{ Switch to terminal }}} +:: + + pas<TAB><TAB> + ~/<TAB><TAB> + +.. R18 + +Bash also saves the history of the commands you have typed. So, you can go +back to a previously typed command and use the up and down arrow keys to +navigate in your bash history. + +.. L18 +:: + + <UP-ARROW> + +.. R19 + +You can also search incrementally, for commands in your bash history. +``Ctrl-r`` searches for the commands that you have typed before. But, note +that the number of commands saved in the history is limited, generally upto +a 1000 commands. + +.. L19 +:: + + <Ctrl-r> pas + +.. R20 + +Unix recognizes certain special characters, called "meta characters," as +command directives. The shell meta characters are recognized anywhere they +appear in the command line, even if they are not surrounded by blank space. +For that reason, it is safest to only use the characters A-Z, a-z, 0-9, and +the period, dash, and underscore characters when naming files and +directories on Unix. If your file or directory has a shell meta character +in the name, you will find it difficult to use the name in a shell command. + +.. L20 + +.. L21 + +{{{ Show slide, with Shell Meta Characters }}} + +.. R21 + +The characters that you can see on the slide are the shell meta characters + +.. R22 + +Lets take an example, + +.. L22 + +{{{ Switch to terminal }}} +:: + + ls file.? + +.. R23 + +It means, run on a directory containing the files file, file.c, file.lst, +and myfile would list the files file.c and file.lst. However, + +.. L23 +:: + + ls file.? + +.. R24 + +Run on the same directory would only list file.c because the ? only matches +one character, no more, no less. This can save you a great deal of typing +time. + +For example, if there is a file called +california_cornish_hens_with_wild_rice and no other files whose names begin +with 'c', you could view the file without typing the whole name by typing +this + +.. L24 +:: + + more c* + +.. R25 + +Here, the c* matches that long file name. +File-names containing meta characters can pose many problems and should +never be intentionally created. + +.. L25 + +.. L26 + +{{{ Switch to Summary slide }}} + +.. R26 + +This brings us to the end of the end of this tutorial. +In this tutorial, we have learnt to, + + 1. Use the ``cut`` and ``paste`` commands in redirection. + #. Use the pipe ( | ) character. + #. Implement features of shell like tab-completion and history. + +.. L27 + +{{{ Show self assessment questions slide }}} + +.. R27 + +Here are some self assessment questions for you to solve + +.. L28 + +{{{ Solution of self assessment questions on slide }}} + +.. R28 + +And the answers, + +.. L29 + +{{{ Show the Thank you slide }}} + +.. R29 + +Hope you have enjoyed this tutorial and found it useful. +Thank you! + diff --git a/ult/ult_4/students.txt b/ult/ult_4/students.txt new file mode 100644 index 0000000..ddacd6b --- /dev/null +++ b/ult/ult_4/students.txt @@ -0,0 +1,5 @@ +Hussain +Dilbert +Anne +Raul +Sven diff --git a/ult/ult_4/ult4.tex b/ult/ult_4/ult4.tex new file mode 100644 index 0000000..3cb3b3a --- /dev/null +++ b/ult/ult_4/ult4.tex @@ -0,0 +1,234 @@ +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +% Using Linux Tools +% +% Author: FOSSEE +% Copyright (c) 2009, FOSSEE, IIT Bombay +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% + +\documentclass[12pt,compress]{beamer} + +\mode<presentation> +{ + \usetheme{Warsaw} + \useoutertheme{infolines} + \setbeamercovered{transparent} +} + +\usepackage[english]{babel} +\usepackage[latin1]{inputenc} +%\usepackage{times} +\usepackage[T1]{fontenc} + +% Taken from Fernando's slides. +\usepackage{ae,aecompl} +\usepackage{mathpazo,courier,euler} +\usepackage[scaled=.95]{helvet} + +\definecolor{darkgreen}{rgb}{0,0.5,0} + +\usepackage{listings} +\lstset{language=sh, + basicstyle=\ttfamily\bfseries, + commentstyle=\color{red}\itshape, + stringstyle=\color{darkgreen}, + showstringspaces=false, + keywordstyle=\color{blue}\bfseries} + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +% DOCUMENT STARTS +\begin{document} + +\begin{frame} + +\begin{center} +\vspace{12pt} +\textcolor{blue}{\huge Using Linux Tools\\Part IV} +\end{center} +\vspace{18pt} +\begin{center} +\vspace{10pt} +\includegraphics[scale=0.95]{../images/fossee-logo.png}\\ +\vspace{5pt} +\scriptsize Developed by FOSSEE Team, IIT-Bombay. \\ +\scriptsize Funded by National Mission on Education through ICT\\ +\scriptsize MHRD,Govt. of India\\ +\includegraphics[scale=0.30]{../images/iitb-logo.png}\\ +\end{center} +\end{frame} +\begin{frame} +\frametitle{Objectives} +\label{sec-2} + +At the end of this tutorial, you will be able to, +\begin{itemize} +\item Understand what is Redirection and Piping. +\item Learn various features of the shell. +\end{itemize} +\end{frame} + +\begin{frame} +\frametitle{Pre-requisite} +\label{sec-3} + +Spoken tutorial on - +\begin{itemize} +\item Using Linux tools -- Part I +\item Using Linux tools -- Part II +\item Using Linux tools -- Part III +\end{itemize} +\end{frame} + +\begin{frame}[fragile] + \frametitle{Redirection} + + \begin{itemize} + \item The standard output (stdout) stream goes to the display + \item Not always, what we need + \item First solution, redirects output to a file + \item \texttt{>} states that output is redirected; It is + followed by location to redirect + \end{itemize} + \begin{lstlisting} + $ command > file1 + \end{lstlisting} % $ + \begin{itemize} + \item \texttt{>} creates a new file at specified location + \item \texttt{>>} appends to a file at specified location + \end{itemize} +\end{frame} + +\begin{frame}[fragile] + \frametitle{Redirection \ldots} + \begin{itemize} + \item Similarly, the standard input (stdin) can be redirected + \end{itemize} + \begin{lstlisting} + $ command < file1 + \end{lstlisting} % $ + \begin{itemize} + \item input and the output redirection could be combined + \end{itemize} + \begin{lstlisting} + $ command < infile > outfile + \end{lstlisting} % $ + \begin{itemize} + \item Standard error (stderr) is the third standard stream + \item All error messages come through this stream + \item \texttt{stderr} can also be redirected + \end{itemize} +\end{frame} + +\begin{frame}[fragile] + \frametitle{Piping} + \begin{lstlisting} + $ cut -d " " -f 2- marks1.txt \ + | paste -d " " students.txt - + \end{lstlisting} % $ + \begin{itemize} + \item \texttt{-} instead of FILE asks \texttt{paste} to read from + \texttt{stdin} + \item \texttt{cut} command is a normal command + \item the \texttt{|} seems to be joining the two commands + \item Redirects output of first command to \texttt{stdin}, which + becomes input to the second command + \item This is called piping; \texttt{|} is called a pipe + \end{itemize} +\end{frame} + +\begin{frame}[fragile] + \frametitle{Piping \ldots} + \begin{itemize} + \item Roughly same as -- 2 redirects and a temporary file + \end{itemize} + \begin{lstlisting} + $ command1 > tempfile + $ command2 < tempfile + $ rm tempfile + \end{lstlisting} % $ + \begin{itemize} + \item Any number of commands can be piped together + \end{itemize} +\end{frame} + +\subsection{Features of the Shell} + +\begin{frame}[fragile] + \frametitle{Tab-completion} + \begin{itemize} + \item Bash provides tab completion for the following. + \begin{enumerate} + \item File Names + \item Directory Names + \item Executable Names + \item User Names (when they are prefixed with a \~{}) + \item Host Names (when they are prefixed with a @) + \item Variable Names (when they are prefixed with a \$) + \end{enumerate} + \end{itemize} +\end{frame} + +\begin{frame}[fragile] + \frametitle{Shell Meta Characters} + \begin{itemize} + \item ``meta characters'' are special command directives + \item File-names shouldn't have meta-characters + \item The following are the shell meta characters -- + \begin{itemize} + \item \verb+/<>!$%^&*|{}[]"'`~;+ + \end{itemize} + \end{itemize} +\end{frame} + +\begin{frame} +\frametitle{Summary} +\label{sec-8} + + In this tutorial, we have learnt to, + + +\begin{itemize} +\item Use the ``cut'' and ``paste'' commands in redirection. +\item Use the pipe ( | ) character. +\item Implement features of shell like tab-completion and history. +\end{itemize} +\end{frame} +\begin{frame}[fragile] +\frametitle{Evaluation} +\label{sec-9} + + +\begin{enumerate} +\item +\item +\item +\end{enumerate} +\end{frame} +\begin{frame} +\frametitle{Solutions} +\label{sec-10} + + +\begin{enumerate} +\item +\vspace{15pt} +\item +\end{enumerate} +\end{frame} +\begin{frame} + + \begin{block}{} + \begin{center} + \textcolor{blue}{\Large THANK YOU!} + \end{center} + \end{block} +\begin{block}{} + \begin{center} + For more Information, visit our website\\ + \url{http://fossee.in/} + \end{center} + \end{block} +\end{frame} + +\end{document} + + |