diff --git a/document.tex b/document.tex
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+++ b/document.tex
@@ -1,1159 +1,1159 @@
 
 \note{
   ##Course duration
 
   0.5 day
 
   ##Description
 
   The goal of this course is to give the basis on the usage of a Linux system in
   order for the user to be able to use the general purpose clusters, and to feel
   at ease like a penguin in cold water.
 
   ##Contents:
 
   - Overview of Linux
   - Connecting to a remote machine (from Linux, Windows or Mac)
   - Using a Linux/Unix system with only the command line
   - Basics on file organization
   - Common shell commands
   - Writing a shell script
 
   ##Prerequisites:
 
   Participants are asked to bring their laptop in order for the training to be
   personalized to their specific environment.
 }
 
 
 \begin{frame}
 
   \begin{minipage}{0.3\textwidth}
     \centering
     \includegraphics[width=3cm]{images/Tux}
   \end{minipage}
   \begin{minipage}{0.5\textwidth}
     \titlepage
     \centering
     \url{c4science.ch/u/linux}
   \end{minipage}
 
 \end{frame}
 
 \section{Overview of Linux}
 
 \begin{frame}{What is Linux}
 
   \begin{minipage}{0.7\linewidth}
     \begin{block}{Just for fun}
       \begin{itemize}
       \item 1991 Linus Torvalds starts Linux ``for fun''
       \item \emph{``I'm doing a (free) operating system (just a hobby, won't be big and professional like gnu) for 386(486) AT clones.''}
       \end{itemize}
     \end{block}
   \end{minipage}
   \hspace*{0.5ex}
   \begin{minipage}{0.25\linewidth}
     \centering
     \vspace*{1.2ex}
     \includegraphics[clip=true, trim=0 50px 0 30px,width=\linewidth]{images/220px-Linus_Torvalds}
   \end{minipage}
   \hspace*{0.5ex}
   \begin{block}{What is a Linux distribution}
     \begin{itemize}
     \item Linux Kernel + softwares
     \item Desktop distributions: windowing system (X11, Wayland), desktop manager
       (GNOME, KDE), package manager (apt, yum), service manager (SystemD)
     \item Common distributions: Debian, Ubuntu, Redhat, ArchLinux
     \end{itemize}
   \end{block}
 \end{frame}
 
 \begin{frame}{What is Linux}
   \begin{minipage}{0.25\linewidth}
     \centering
     \includegraphics[width=3.5\textwidth]{images/Linux_kernel_map}
   \end{minipage}
 \end{frame}
 
 \begin{frame}{What is Linux}
   \begin{minipage}{0.25\linewidth}
     \centering
     \includegraphics[width=4.0\textwidth]{images/linux-distrib}
   \end{minipage}
 \end{frame}
 
 \begin{frame}{Where can you find Linux}
   \begin{minipage}{0.45\linewidth}
     \begin{block}{Supercomputers}
       \centering
       \includegraphics[width=\linewidth]{images/top_500_2019}
     \end{block}
   \end{minipage}
   \hspace*{2ex}
   \begin{minipage}{0.45\linewidth}
     \begin{block}{Smartphones}
       \centering
       \includegraphics[width=\linewidth]{images/smartphones_2018}
     \end{block}
   \end{minipage}
 
   \begin{block}{Other numbers}
     \begin{itemize}
     \item Desktop: 2.91\%
     \item Servers (web): 77.4\%
     \item Servers (mainframe): 28\%
     \item Embedded: 38.42\%
     \end{itemize}
   \end{block}
 \end{frame}
 
 \section{Login}
 
 \begin{frame}{Login}
   \begin{block}{First step: get a shell}
     \begin{itemize}
     \item Shell: user interface to the operating system's services
     \item Start a shell on your local machine
     \item Connect to a remote machine to get a shell
     \item SSH: Secure SHell
     \end{itemize}
   \end{block}
 
   \vspace{2ex}
 
   \begin{minipage}{.45\linewidth}
     \begin{block}{Windows}
       \begin{itemize}
       \item \href{https://docs.microsoft.com/en-us/windows/wsl/install-win10}{Windows Subsystem for Linux (WSL)}
       \item \href{https://git-scm.com/downloads}{Git Bash}
       \end{itemize}
     \end{block}
   \end{minipage}
   \hspace*{4.5ex}
   \begin{minipage}{.45\linewidth}
     \begin{block}{Linux/OSX}
       \begin{itemize}
       \item Start a terminal
       \end{itemize}
     \end{block}
   \end{minipage}
 \end{frame}
 
 \begin{frame}{Login}
   \begin{block}{Terminal}
     \centering
     \begin{tikzonimage}[scale=1.2]{images/terminal}
       \draw[thick, red] (0.8cm, 5.1cm) --
                         (0.8cm, 4.8cm) --
                         (3.8cm, 4.8cm) --
                         (3.8cm, 5.1cm) -- cycle;
       \node (host) at (3cm, 4.55cm) {};
       \node[red] (hostname) at (3.5cm, 2.5cm) {\code{ssh -l $<$username$>$ $<$hostname$>$}};
       \path[-latex, thick, red] (hostname) edge [bend left] (host);
     \end{tikzonimage}
   \end{block}
 \end{frame}
 
 \begin{frame}{Some usefull commands}
   \begin{block}{}
     \centering
     \begin{tabular}{r|l}
       \code{ls}          & list files\\
       \code{cd}          & change directory\\
       \code{pwd}         & path of the current directory\\
       & \\
       \code{man}         & get help on commands\\
       \code{apropos}     & search for a command and print a brief description\\
       \code{echo}        & print the arguments in the terminal \\
     \end{tabular}
   \end{block}
 \end{frame}
 
 \begin{exo}{First commands}
   \begin{extrainfos}
 
     List of usefull commands:
 
     \vspace{1ex}
     \begin{tabular}{r|l}
       \code{ls}          & list files\\
       \code{cd}          & change directory\\
       \code{pwd}         & path of the current \\
       \code{man}         & get help on commands\\
       \code{apropos}     & search for a command and print a brief description\\
       \code{echo}        & print the arguments in the terminal \\
     \end{tabular}
   \end{extrainfos}
 
   \begin{questions}
-    \item Connect to the remote machine \code{scitascours1.epfl.ch}.
+    \item Connect to the remote machine \code{fidis.epfl.ch}.
     \item Check your current folder and your files.
     \item Check the help of \code{ls} (\texttt{Q} to quit).
   \end{questions}
 
   \begin{block}<2->{}
     \begin{command}
   > pwd
   > ls%
     \end{command}
   \end{block}
 
   \begin{block}<3->{}
     \begin{command}
   > man ls%
     \end{command}
   \end{block}
 
 \end{exo}
 
 \section{File-system}
 
 \begin{frame}{File structure}
   \begin{block}{``On UNIX everything is a file''}
     \begin{tabular}{rl}
     \textbf{Directories}          & files that are lists of other files\\
     \textbf{Special files}        & files for input/output mechanisms\\
     \textbf{Links}                & way to make files visible in different parts\\
                                   & of the file system\\
     \textbf{Sockets,}             & way to communicate between processes\\
     \textbf{named pipes}          & \\
     \end{tabular}
   \end{block}
 \end{frame}
 
 \begin{frame}{Tree view}
   \begin{block}{}
     \centering
     \begin{tikzpicture}[every node/.style=draw=black,thick,anchor=west,text depth=.5ex,text height=2.2ex]
       \node {/}
       child { node {etc/}}
       child { node {usr/}
         child { node {bin/}}
         child { node {lib/}}
       }
       child [missing] {}
       child { node {home/}
         child { node (a) {user1/}
           child { node {Download/}}
           child [missing] {}
           child { node (b) {Desktop/}}
         }
         child [missing] {}
         child { node {user2/}}
       };
     \end{tikzpicture}
   \end{block}
 \end{frame}
 
 \begin{frame}{File structure}
   \begin{block}{Standard directories}
     \begin{tabular}{ll}
     \textbf{/etc}   & System configurations files\\
     \textbf{/boot}  & Boot files, kernel and boot loader\\
     \textbf{/home}  & User accounts\\
     \textbf{/usr}   & Software, libraries, documentations, for user programs \\
     \textbf{/var}   & Variables files such as log files, mail queues, databases \\
     \textbf{/opt}   & Third-party and extra softwares\\
     \end{tabular}
   \end{block}
   \begin{block}{Virtual directories}
     \begin{tabular}{ll}
     \textbf{/dev}   & Peripheral hardware related files \\
     \textbf{/proc}  & Informations about processes\\
     \textbf{/sys}  & Informations about the kernel\\
     \end{tabular}
   \end{block}
 \end{frame}
 
 
 \begin{exo}{Directory structure}
   \begin{questions}
     \item Show directory structure under the root folder
     \item Change directory to the root folder and list the content
   \end{questions}
 
   \begin{block}<2->{}
       \begin{command}
   > ls /%
       \end{command}
   \end{block}
 
   \begin{block}<3->{}
     \begin{command}
   > cd /
   > ls%
     \end{command}
   \end{block}
 \end{exo}
 
 \begin{frame}{Relative/absolute path}
   \newcommand*\redcolor{}
   \newcommand*\bluecolor{}
   \newcommand*\fillbluecolor{none}
   \only<1-3>{\renewcommand*\redcolor{red}}
   \only<4->{\renewcommand*\bluecolor{blue}}
   \only<4->{\renewcommand*\fillbluecolor{blue!20}}
   \begin{block}{}
     \centering
     \begin{tikzpicture}[every node/.style=draw=black,thick,anchor=west,text depth=.5ex,text height=2.2ex]
       \node[\bluecolor] {/}
       child { node {etc/}}
       child { node {usr/}
         child { node {bin/}}
         child { node {lib/}}
       }
       child [missing] {}
       child { node[\bluecolor] (p) {home/}
         child [missing] {}
         child { node[\bluecolor,\redcolor,fill=\fillbluecolor] (n) {user1/}
           child { node {Download/}}
           child [missing] {}
           child { node[\bluecolor] {Desktop/}}
           child [missing] {}
           child { node[\redcolor] (dot) {.}}
           child { node[\redcolor] (ddot) {..}}
         }
         child [missing] {}
         child [missing] {}
         child { node {user2/}}
       };
       \path[\redcolor, -latex, visible on=<2-3>] (dot) edge [bend right] (n);
       \path[\redcolor, -latex, visible on=<3-3>] (ddot) edge [bend right] (p);
     \end{tikzpicture}
   \end{block}
 
   \begin{block}<4->{}
     \code{/home/user1/Desktop}\\
     \code{./Desktop}
   \end{block}
 \end{frame}
 
 \begin{exo}{Relative/absolute path}
   \begin{questions}
   \item Try the command \code{ls -a}
   \item List the parent folder of your home
   \item List the root folder with a relative path
   \item To what correspond the folder \code{../././..}
   \end{questions}
   \vspace*{-.7ex}
   \begin{block}<2->{}
       \begin{command}
   > ls ../%
       \end{command}
   \end{block}
   \vspace*{-.7ex}
   \begin{block}<3->{}
       \begin{command}
   > ls ../../%
       \end{command}
   \end{block}
   \vspace*{-.7ex}
   \begin{block}<4->{}
       \begin{command}
   > cd ../././..
   > pwd %
       \end{command}
   \end{block}
 \end{exo}
 
 \begin{frame}{File creation/suppression commands}
     \begin{block}{}
     \centering
     \begin{tabular}{r|l}
       \code{cp}       & copy files\\
       \code{mv}       & move/rename files\\
       \code{rm}       & remove file \color{red}{caution no trash}\\
       \code{mkdir}    & create a folder\\
       \code{cat}      & print the content of file, used to concatenate\\
       \code{touch}    & update the date of a file, used to create empty files\\
       \code{tail/head}& print the end/beginning of a file\\
       \code{more/less}& print the content of a file ``more or less the same''\\
       \code{grep}     & search a string in a file\\
       \code{find}     & find a file\\
       \code{file}     & the type of file based on content
     \end{tabular}
   \end{block}
 \end{frame}
 
 \begin{exo}{File handling commands}
   \begin{extrainfos}
     \centering
     \begin{tabular}{r|l}
       \code{cp}       & copy files\\
       \code{mv}       & move/rename files\\
       \code{rm}       & remove file \color{red}{caution no trash}\\
       \code{mkdir}    & create a folder\\
       \code{cat}      & print the content of file, used to concatenate\\
       \code{touch}    & update the date of a file, used to create empty files\\
       \code{tail/head}& print the end/beginning of a file\\
       \code{more/less}& print the content of a file ``more or less the same''\\
       \code{grep}     & search a string in a file\\
       \code{find}     & find a file\\
       \code{file}     & the type of file based on content
     \end{tabular}
   \end{extrainfos}
 
   \begin{questions}
   \item Test the different commands (do not forget you can check the help with
     \code{man <command>})
   \item Create a directory named \code{exercise\_linux}
   \item Copy the file \code{CodingStyle} from your home directory into the \code{exercise\_linux} folder
   \item Check the content of this file
   \item Print the last 3 lines
   \item Find the lines containing the world ``coding'' independently of the case
   \item Rename the file as \code{KernelCodingStyle}
   \item Copy the folder \code{exercise\_linux} to \code{exo\_linux}
   \item Remove the folder \code{exercise\_linux}
   \end{questions}
 \end{exo}
 
 \begin{frame}[fragile]{Answer to exercise~\arabic{exercise}}
   \begin{block}{}
     \vspace*{-.8ex}
     \begin{command}
   > mkdir exercise_linux %
     \end{command}
     \vspace*{-1.4ex}
   \end{block}
 
   \vspace*{-1.1ex}
   \begin{block}<2->{}
     \vspace*{-.8ex}
     \begin{command}
   > cd exercise_linux
   > cp /ssoft/playground/richart/CodingStyle .%
     \end{command}
     \vspace*{-1.4ex}
   \end{block}
 
   \vspace*{-1.1ex}
   \begin{block}<3->{}
     \vspace*{-.8ex}
     \begin{command}
   > less CodingStyle%
     \end{command}
     \vspace*{-1.4ex}
   \end{block}
 
   \vspace*{-1.1ex}
   \begin{block}<4->{}
     \vspace*{-.8ex}
     \begin{command}
   > tail -n3 CodingStyle%
     \end{command}
     \vspace*{-1.4ex}
   \end{block}
 
   \vspace*{-1.1ex}
   \begin{block}<5->{}
     \vspace*{-.8ex}
     \begin{command}
   > grep -n --color -i coding CodingStyle%
     \end{command}
     \vspace*{-1.4ex}
   \end{block}
 
   \vspace*{-1.1ex}
   \begin{block}<6->{}
     \vspace*{-.8ex}
     \begin{command}
   > mv CodingStyle KernelCodingStyle%
     \end{command}
     \vspace*{-1.4ex}
   \end{block}
 
   \vspace*{-1.1ex}
   \begin{block}<7->{}
     \vspace*{-.8ex}
     \begin{command}
   > cd ..
   > cp -r exercise_linux exo_linux%
     \end{command}
     \vspace*{-1.4ex}
   \end{block}
 
   \vspace*{-1.1ex}
   \begin{block}<8->{}
     \vspace*{-.8ex}
     \begin{command}
   > rm -r exercise_linux %
     \end{command}
     \vspace*{-1.4ex}
   \end{block}
 \end{frame}
 
 \begin{frame}{File permissions}
   \begin{block}{Possible permissions}
     Partial results of the command \code{ls -l CodingStyle}\\
     \texttt{-}\tikz[baseline]{ \node[anchor=base, fill=blue!20 ] (u1) {\texttt{rw-}}; }
               \tikz[baseline]{ \node[anchor=base, fill=red!20  ] (g1) {\texttt{r--}}; }
               \tikz[baseline]{ \node[anchor=base, fill=green!20] (o1) {\texttt{r--}}; }
               \hspace*{1em}\texttt{richart} \hspace*{1em}\texttt{scitas-ge}
               \hspace*{1ex}\texttt{CodingStyle}
     \begin{itemize}
     \item[] \tikz[baseline]{ \node[anchor=base, fill=blue!20 ] (u1)
         {u}; } User permissions
     \item[] \tikz[baseline]{ \node[anchor=base, fill=red!20 ] (u1)
         {g}; } Group permissions
     \item[] \tikz[baseline]{ \node[anchor=base, fill=green!20 ] (u1)
         {o}; } Other users permissions
     \end{itemize}
   \end{block}
 
   \begin{block}{\texttt{rwx}/\texttt{---} explanations}
     \begin{tabular}{r|l}
       \code{-} or 0 & Permission not granted \\
       \code{r} or 4 & Read/List permission        \\
       \code{w} or 2 & Write/Create permission       \\
       \code{x} or 1 & Execute/Traverse permission\\
     \end{tabular}
   \end{block}
 \end{frame}
 
 \begin{frame}{Permission commands}
   \begin{block}{}
     \begin{tabular}{r|l}
       \code{chmod}  & change permissions \\
       \code{chgrp}  & change main group  \\
       \code{chown}  & change ownership   \\
       \code{newgrp} & login with a new group as main group \\
       \code{id}     & print user and group ids \\
     \end{tabular}
   \end{block}
 
   \begin{block}{\texttt{chmod} details}
     \code{chmod [ugoa][+-=][rwxXst] files}\\
     \code{chmod octal files}
 
     example: \code{u=rw,go=r} equivalent to \code{644}
   \end{block}
 \end{frame}
 
 \begin{exo}{Permissions}
   \begin{extrainfos}
     Partial results of the command \code{ls -l CodingStyle}\\
     \texttt{-}\tikz[baseline]{ \node[anchor=base, fill=blue!20 ] (u1) {\texttt{rw-}}; }
               \tikz[baseline]{ \node[anchor=base, fill=red!20  ] (g1) {\texttt{r--}}; }
               \tikz[baseline]{ \node[anchor=base, fill=green!20] (o1) {\texttt{r--}}; }
               \hspace*{1em}\texttt{richart} \hspace*{1em}\texttt{scitas-ge}
               \hspace*{1ex}\texttt{CodingStyle}
     \begin{itemize}
       \setlength\itemsep{.1em}
     \item[] \tikz[baseline]{ \node[anchor=base, fill=blue!20 ] (u1)
         {u}; } User permissions
     \item[] \tikz[baseline]{ \node[anchor=base, fill=red!20 ] (u1)
         {g}; } Group permissions
     \item[] \tikz[baseline]{ \node[anchor=base, fill=green!20 ] (u1)
         {o}; } Other users permissions
     \end{itemize}
 
 
     \begin{tabular}{r|l}
       \code{-} or 0 & Permission not granted \\
       \code{r} or 4 & Read/List permission        \\
       \code{w} or 2 & Write/Create permission       \\
       \code{x} or 1 & Execute/Traverse permission\\
     \end{tabular}
 
     \begin{tabular}{r|l}
       \code{chmod}  & change permissions \\
       \code{chgrp}  & change main group  \\
       \code{chown}  & change ownership   \\
       \code{newgrp} & login with a new group as main group \\
       \code{id}     & print user and group ids \\
     \end{tabular}
   \end{extrainfos}
 
 
   \begin{questions}
   \item Print your ids
   \item Check the permissions of your home folders
   \item Change the the default group of the file \code{KernelCodingStyle} to \code{hpc-cluster-users}
   \item Remove the list permission on \code{exo\_linux}
   \item Try to list the \code{exo\_linux} folder of someone that as completed
     the previous step
   \end{questions}
 \end{exo}
 
 \begin{frame}[fragile]{Answer to exercise~\arabic{exercise}}
   \begin{block}{}
     \vspace*{-.8ex}
     \begin{command}
   > id %
     \end{command}
     \vspace*{-1.4ex}
   \end{block}
 
   \vspace*{-1.1ex}
   \begin{block}<2->{}
     \vspace*{-.8ex}
     \begin{command}
   > ls -l %
     \end{command}
     \vspace*{-1.4ex}
   \end{block}
 
   \vspace*{-1.1ex}
   \begin{block}<3->{}
     \vspace*{-.8ex}
     \begin{command}
   > chgrp hpc-cluster-users exo_linux/KernelCodingStyle %
     \end{command}
     \vspace*{-1.4ex}
   \end{block}
 
   \vspace*{-1.1ex}
   \begin{block}<4->{}
     \vspace*{-.8ex}
     \begin{command}
   > chmod go-r exo_linux%
     \end{command}
     \vspace*{-1.4ex}
   \end{block}
 
   \vspace*{-1.1ex}
   \begin{block}<5->{}
     \vspace*{-.8ex}
     \begin{command}
   > ls -l /home/richart/exo_linux
   > ls -l /home/richart/exo_linux/KernelCodingStyle%
     \end{command}
     \vspace*{-1.4ex}
   \end{block}
 \end{frame}
 
 \begin{frame}{Permissions: the special case of \texttt{root}}
   \begin{block}{The \texttt{root} account}
     \begin{itemize}
     \item It's a special account, to which regular permissions do not apply
     \item Used to administer the system
     \item Should only be used to install trusted software
     \item Preferably via the \code{sudo} command
     \end{itemize}
   \end{block}
 \end{frame}
 
 \section{Shell}
 
 \vspace{-.2cm}
 \begin{frame}{More about Shell}
   \begin{block}{}
     \begin{itemize}
     \item Different shells: \texttt{sh}, \texttt{bash}, \texttt{csh}, \texttt{tcsh}, \texttt{zsh}, etc.
     \item For EPFL account: {\scriptsize\url{https://cadiwww.epfl.ch/cgi-bin/accountprefs/}}
     \item In general \code{echo \$SHELL}
     \end{itemize}
   \end{block}
 
   \vspace{-.2cm}
   \begin{block}{What is happening when you run a command}
     \begin{itemize}
     \item Expansions
     \item Redirection
     \item Execution
     \end{itemize}
   \end{block}
 
   \vspace{-.2cm}
   \begin{block}{Key shortcuts}
     \begin{tabular}{r|l}
       \texttt{Tab}  & auto-complete \\
       \texttt{(up)}    & go back in the command history  \\
       \texttt{(down)}  & go down in the command history  \\
       \texttt{Ctrl-r}  & reverse search in the history  \\
       \texttt{Ctrl-d}    & exit the shell  \\
     \end{tabular}
   \end{block}
 
 \end{frame}
 
 \begin{frame}[fragile]{Expansions}
   \begin{block}{}
     \begin{itemize}
     \item Accolade: \code{\{a\{b,c\},d\}} $\longrightarrow$ \code{ab ac d}
     \item Tilde: \code{\textasciitilde richart/} $\longrightarrow$ \code{/home/richart}
     \item Variables: \code{export FOO=bar}  \code{\$FOO} $\longrightarrow$ \code{bar}
     \item Command: \code{\$(command)} $\longrightarrow$ result of command
     \item Split spaces: \code{arg1 arg2 arg3} the quoted arguments are not split
     \item Path: \code{*} matches any string\\
       \hspace{2.4em} \code{?} matches any single character\\
       \hspace{2.4em} \code{[...]} matches any character in the brackets
     \end{itemize}
   \end{block}
   \begin{itemize}
   \item \textbf{TIP:} use \code{echo <command>} to test your expansions \!
   \end{itemize}
 \end{frame}
 
 \begin{exo}{Expansions}
   \begin{extrainfos}
     \begin{tabular}{r|l}
       \code{touch}  & change the date of a file used to create new files \\
       \code{echo}   & print to the screen  \\
       \code{export} & make a variable known in all the new subprocess   \\
     \end{tabular}
   \end{extrainfos}
 
   \begin{questions}
   \item Try the command \code{touch file\{0,1,2\}\{0,1,2,3,4,5\}.log}
   \item List your home folder with a tilde expression
   \item Set a variable \code{FOO} to the content of your choice and print its
     content
   \item Try the commands:\\
     \code{touch foo bar}\\
     \code{touch "foo bar"}\\
     \code{export BROL=brol}\\
     \code{touch "foo bar \$BROL"}\\
     \code{touch 'foo bar \$BROL'}
   \item List all file of the form \code{file<number>.log}
   \item List the files  \code{file<number>.log} where \texttt{<}number\texttt{>} is any number
     with last digit 2,3 or 4
   \item Remove the previous files using the results of the ls command
   \end{questions}
 \end{exo}
 
 \begin{frame}[fragile]{Answer to exercise~\arabic{exercise}}
   \vspace*{-1.1ex}
   \begin{block}<1->{}
     \vspace*{-.8ex}
     \begin{command}
   > ls ~/%
     \end{command}
     \vspace*{-1.4ex}
   \end{block}
 
   \vspace*{-1.1ex}
   \begin{block}<2->{}
     \vspace*{-.8ex}
     \begin{command}
   > export FOO="the content of my choice"
   > echo $FOO%
     \end{command} %$
     \vspace*{-1.4ex}
   \end{block}
 
   \vspace*{-1.1ex}
   \begin{block}<3->{}
     \vspace*{-.8ex}
 The second command create a file name containing a space that can be escaped
 with \code{\textbackslash}
     \begin{command}
   > rm foo\ bar foo bar foo\ bar\ \$BROL foo\ bar\ brol%
     \end{command}
     \vspace*{-1.4ex}
   \end{block}
 
   \vspace*{-1.1ex}
   \begin{block}<4->{}
     \vspace*{-.8ex}
     \begin{command}
   > ls file*.log %
     \end{command}
     \vspace*{-1.4ex}
   \end{block}
 
   \vspace*{-1.1ex}
   \begin{block}<5->{}
     \vspace*{-.8ex}
     \begin{command}
   > ls file{2..4}.log %
     \end{command}
     \vspace*{-1.4ex}
   \end{block}
 
   \vspace*{-1.1ex}
   \begin{block}<6->{}
     \vspace*{-.8ex}
     \begin{command}
   > rm $(ls file*.log) %
     \end{command}
     \vspace*{-1.4ex}
   \end{block}
 \end{frame}
 
 \begin{frame}[fragile]{Redirection}
   \begin{block}{\texttt{process}}
     \centering
     \begin{tikzpicture}
       \node [draw,text width=9ex,text height=3ex,text centered,text depth=2ex] (p) {process};
       \node (i) at (-2.5cm,  0cm) {stdin (0) };
       \node (o) at ( 2.5cm, .4cm) {stdout (1)};
       \node (e) at ( 2.5cm,-.4cm) {stderr (2)};
       \draw (i) -- (p);
       \draw (p) -- (o);
       \draw (p) -- (e);
     \end{tikzpicture}
   \end{block}
 
   \begin{block}{\texttt{process > file.out}}
     \centering
     \begin{tikzpicture}
       \node [draw,text width=9ex,text height=3ex,text centered,text depth=2ex] (p) {process};
       \node (i) at (-2.5cm,  0cm) {stdin  (0)};
       \node (o) at ( 2.5cm, .4cm) {stdout (1)};
       \node (e) at ( 2.5cm,-.4cm) {stderr (2)};
 
       \node [draw,text width=7ex,text height=2ex,text centered,text depth=1ex]
       (f) at (6cm, .4cm) {file.out};
       \node (s) at (4.5cm, .4cm) {\color{red}{\texttt{>}}};
 
       \draw (i) -- (p);
       \draw (p) -- (o);
       \draw (p) -- (e);
 
       \draw (o) -- (s)  -- (f);
     \end{tikzpicture}
   \end{block}
 
   \begin{block}{\texttt{process 2> file.err}}
     \centering
     \begin{tikzpicture}
       \node [draw,text width=9ex,text height=3ex,text centered,text depth=2ex] (p) {process};
       \node (i) at (-2.5cm,  0cm) {stdin  (0)};
       \node (o) at ( 2.5cm, .4cm) {stdout (1)};
       \node (e) at ( 2.5cm,-.4cm) {stderr (2)};
 
       \node [draw,text width=7ex,text height=2ex,text centered,text depth=1ex]
       (f) at (6cm, -.4cm) {file.err};
       \node (s) at (4.5cm, -.4cm) {\color{red}{\texttt{2>}}};
 
       \draw (i) -- (p);
       \draw (p) -- (o);
       \draw (p) -- (e);
 
       \draw (e) -- (s)  -- (f);
     \end{tikzpicture}
   \end{block}
 \end{frame}
 
 \begin{frame}[fragile]{Redirection}
   \begin{block}{\texttt{process1 | process2}}
     \centering
     \begin{tikzpicture}
       \node [draw,text width=7ex,text height=2ex,text centered,text depth=1.5ex] (p1) {\scriptsize{process1}};
       \node (i1) at (-1.8cm,  0cm) {\scriptsize{stdin  (0)}};
       \node (o1) at ( 1.8cm, .4cm) {\scriptsize{stdout (1)}};
       \node (e1) at ( 1.8cm,-.4cm) {\scriptsize{stderr (2)}};
 
       \node (pipe) at (3cm, .4cm) {\color{red}{\texttt{|}}};
 
       \draw (i1) -- (p1);
       \draw (p1) -- (o1);
       \draw (p1) -- (e1);
 
       \node [draw,text width=7ex,text height=2ex,text centered,text depth=1.5ex]
       (p2) at (5.9cm, .4cm) {\scriptsize{process2}};
       \node (i2) at ( 4.1cm, .4cm) {\scriptsize{stdin  (0)}};
       \node (o2) at ( 7.7cm, .8cm) {\scriptsize{stdout (1)}};
       \node (e2) at ( 7.7cm,  0cm) {\scriptsize{stderr (2)}};
 
       \draw (i2) -- (p2);
       \draw (p2) -- (o2);
       \draw (p2) -- (e2);
 
       \draw (o1) -- (pipe) -- (i2);
     \end{tikzpicture}
   \end{block}
 
   \begin{block}{\texttt{process > file.out 2>\&1}}
     \centering
     \begin{tikzpicture}
       \node [draw,text width=9ex,text height=3ex,text centered,text depth=2ex] (p) {process};
       \node (i) at (-2.5cm,  0cm) {stdin  (0)};
       \node (o) at ( 2.5cm, .4cm) {stdout (1)};
       \node (e) at ( 2.5cm,-.4cm) {stderr (2)};
 
       \node [draw,text width=7ex,text height=2ex,text centered,text depth=1ex]
       (f) at (6cm, .4cm) {file.out};
       \node (s1) at (4.4cm, .4cm) {\color{red}{\texttt{>}}};
 
       \node [draw,text width=7ex,text height=2ex,text centered,text depth=1ex]
       (f) at (6cm, .4cm) {file.out};
       \node (s2) at (4.4cm, -0cm) {\color{red}{\texttt{2>\&1}}};
 
       \draw (i) -- (p);
       \draw (p) -- (o);
       \draw (p) -- (e);
 
       \draw (o) -- (s1)  -- (f);
       \draw (e) -- (s2)  -- (f);
     \end{tikzpicture}
   \end{block}
 \end{frame}
 
 \begin{exo}{Redirection}
   \begin{extrainfos}
     \begin{tabular}{r|l}
       \code{date}  & print the date \\
       \code{wc}   & wc count the numbers of lines/words/characters in a file  \\
     \end{tabular}
 
     \vspace{1.5ex}
     Syntax for redirections:
     \vspace{-1.5ex}
     \begin{itemize}
     \item \code{command > file} redirect the standard output to \texttt{file}
     \item \code{command 2> file} redirect the standard error to \texttt{file}
     \item \code{command < file} redirect \texttt{file} to the standard input
     \item \code{command1 | command2} redirect the stdout of \texttt{command1} in stdin of \texttt{command2}
     \end{itemize}
   \end{extrainfos}
 
   \begin{questions}
   \item Redirect the content of the \code{date} command in the \texttt{date.log} file
   \item Count the number of words generated by the command \code{date} with the
     help of the command \code{wc}
   \item Redirect the error output for the command \code{ls / tmp}
   \end{questions}
 
   \vspace*{-1.1ex}
   \begin{block}<2->{}
     \vspace*{-.8ex}
     \begin{command}
   > date > date.log%
     \end{command}
     \vspace*{-1.4ex}
   \end{block}
 
   \vspace*{-1.1ex}
   \begin{block}<3->{}
     \vspace*{-.8ex}
     \begin{command}
   > date | wc -w%
     \end{command}
     \vspace*{-1.4ex}
   \end{block}
 
   \vspace*{-1.1ex}
   \begin{block}<4->{}
     \vspace*{-.8ex}
     \begin{command}
   > ls / tmp 2> errors%
     \end{command}
     \vspace*{-1.4ex}
   \end{block}
 
 \end{exo}
 
 \begin{frame}{Execution}
   \begin{block}{}
     \begin{itemize}
     \item Execution generate a new process
     \item A process is identified by a \texttt{pid}
     \item Can be run in foreground or background (\code{\&})
     \end{itemize}
   \end{block}
 
   \begin{block}{Commands}
     \begin{tabular}{r|l}
       \code{ps}    & list the running processes \\
       \code{jobs}  & list the jobs running in the current shell  \\
       \code{kill}  & kill processes   \\
       \code{bg}    & resume jobs in background \\
       \code{fg}    & resume jobs in foreground \\
     \end{tabular}
   \end{block}
 
   \begin{block}{Key shortcuts}
     \begin{tabular}{r|l}
       \texttt{Ctrl-c}  & kill the current job in foreground  \\
       \texttt{Ctrl-z}  & suspend the current job in foreground  \\
     \end{tabular}
   \end{block}
 \end{frame}
 
 \begin{exo}{Execution}
   \begin{extrainfos}
     \begin{tabular}{r|l}
       \code{ps}    & list the running processes \\
       \code{jobs}  & list the jobs running in the current shell  \\
       \code{kill}  & kill processes   \\
       \code{bg}    & resume jobs in background \\
       \code{fg}    & resume jobs in foreground \\
     \end{tabular}
   \end{extrainfos}
 
   \begin{questions}
   \item Run the command \code{(sleep 30; echo Slept well)}
   \item Run the command \code{(sleep 30; echo Slept well)\&}
   \item Now you have 30 seconds to check the \texttt{pid} with \code{ps}
   \item If you still have spare seconds kill the process before it print on screen
   \end{questions}
 \end{exo}
 
 \section{Editing files}
 
 \begin{frame}{Command line editors: nano vi emacs}
   \begin{block}{nano}
     \begin{itemize}
     \item \code{Ctrl-o} to save file
     \item \code{Ctrl-x} to quit
     \end{itemize}
   \end{block}
 
   \begin{block}{vi}
     \begin{itemize}
     \item command mode and edition mode
     \item \code{i} to insert, \code{esc} to go back to command mode
     \item \code{:wq} to save and quit
     \item \code{:q!} to force quit
     \end{itemize}
   \end{block}
 
   \begin{block}{emacs}
     \begin{itemize}
     \item \code{Ctrl-x Ctrl-s} to save file
     \item \code{Ctrl-x Ctrl-c} to quit
     \end{itemize}
   \end{block}
 
 \end{frame}
 
 \begin{exo}{Execution}
   \begin{extrainfos}
     \begin{itemize}
     \item nano\\
       \begin{tabular}{r|l}
         \code{Ctrl-o} & save file \\
         \code{Ctrl-x} & quit \\
       \end{tabular}
     \item vi\\
       \begin{tabular}{r|l}
         \code{i} & insert \\
         \code{esc} & go back to command mode \\
         \code{:wq} & save and quit\\
         \code{:q!} & force quit\\
       \end{tabular}
 
     \item emacs\\
       \begin{tabular}{r|l}
         \code{Ctrl-x Ctrl-s} & save file \\
         \code{Ctrl-x Ctrl-c} & quit\\
       \end{tabular}
     \end{itemize}
   \end{extrainfos}
 
   \begin{questions}
   \item Try this editors
   \begin{itemize}
       \item nano
       \item vim
       \item emacs
   \end{itemize}
   \end{questions}
 \end{exo}
 
 \section{Scripts}
 
 \begin{frame}{Shell scripts}
   \begin{block}{What is it}
     \begin{itemize}
     \item It is a file containing a list of commands to execute in order
     \item Can contain loops (\texttt{for}, \texttt{while}), conditions
       (\texttt{if})
     \item Often start with interpreter information \code{\#!/bin/bash}
     \end{itemize}
   \end{block}
 
   \begin{block}{Example of bash script}
     \begin{itemize}
     \item \texttt{\textasciitilde/.bashrc}
     \item cluster job script
     \end{itemize}
   \end{block}
 \end{frame}
 
 \begin{exo}{Shell scripts}
   \begin{questions}
   \item Write a script that print \texttt{Hello World}, wait 2seconds and then
     print the date
   \item Make your script executable
   \item Run it
   \end{questions}
 
   \begin{block}<2->{hello.sh}
     \vspace*{-.8ex}
     \begin{command}
   #!/bin/bash
   echo Hello World
   sleep 2
   date%
     \end{command}
     \vspace*{-1.4ex}
   \end{block}
   \begin{block}<3->{}
     \vspace*{-.8ex}
     \begin{command}
   > chmod +x ./hello.sh%
     \end{command}
     \vspace*{-1.4ex}
   \end{block}
   \begin{block}<4->{}
     \vspace*{-.8ex}
     \begin{command}
   > ./hello.sh%
     \end{command}
     \vspace*{-1.4ex}
   \end{block}
 \end{exo}
 
 %\section{Extra Material}
 
 \begin{frame}{Transferring files: SFTP clients}
   \begin{minipage}{.45\linewidth}
     \begin{block}{Filezilla}
       {\scriptsize\url{https://filezilla-project.org}}
       \centering
       \begin{tikzonimage}[width=.96\linewidth]{images/filezilla}
       \end{tikzonimage}
       \vspace*{3.5ex}
     \end{block}
   \end{minipage}
   \hspace*{2ex}
   \begin{minipage}{.45\linewidth}
     \begin{block}{Cyberduck}
       {\scriptsize\url{https://cyberduck.io/}}
       \centering
       \begin{tikzonimage}[width=.96\linewidth]{images/cyberduck}
       \end{tikzonimage}
     \end{block}
   \end{minipage}
 \end{frame}
 
 \begin{frame}{X11 Forwarding}
   \begin{block}{Windows}
     Install XMing {\scriptsize\url{http://sourceforge.net/projects/xming/}} or
     XWin32 (distrilog)\\
   \end{block}
   \vspace*{-1ex}
   \begin{block}{Mac OS}
     Install XQuartz {\scriptsize\url{http://xquartz.macosforge.org/landing/}}, MacPort or Homebrew\\
 
     Connect with \code{ssh -Y <username>@<hostname>}
   \end{block}
 
 \end{frame}
 
 %\section{Sources}
 
 \begin{frame}{Sources}
   \begin{block}{}
     \begin{itemize}
     \item Wikipedia: \url{http://en.wikipedia.org/}
       \begin{itemize}
       \item \href{https://en.wikipedia.org/wiki/History_of_Linux}{History\_of\_Linux}
       \item \href{https://en.wikipedia.org/wiki/Usage_share_of_operating_systems}{Usage\_share\_of\_operating\_systems}
       \item \href{https://en.wikipedia.org/wiki/Mobile_operating_system}{Mobile\_operating\_system}
       \end{itemize}
     \item DistroWatch: \url{http://distrowatch.com/}
     \item \href{http://tldp.org/LDP/intro-linux/html/}{The Linux Documentation Project}
     \end{itemize}
   \end{block}
 \end{frame}
 
 
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