\documentclass{ltxdoc} % Process with xelatex -shell-escape
\usepackage{bashful}

\usepackage[colorlinks=true]{hyperref}
\usepackage{gensymb}
\usepackage{graphicx}
\usepackage{metalogo}
\usepackage{xkvview}
\usepackage{xspace}
\usepackage{amsmath}


\newcommand\me{bashful}
\newcommand\bashful{\textsf{\me}\xspace}
  \lstdefinestyle{input}{
    basicstyle=\ttfamily, 
    showstringspaces=false,
    aboveskip=0pt,
    belowskip=0pt}%

\title{The \bashful Package\thanks{
  This work may be distributed and/or modified under the conditions of the
    \emph{GNU GENERAL PUBLIC LICENSE}{http://www.gnu.org/licenses/gpl.html}.
The latest version of this license is in 
  \url{http://www.latex-project.org/lppl.txt} and version 1.3 or later 
  is part of all distributions of \LaTeX{} version 2005/12/01 or later.
This work has the LPPL maintenance status `maintained'.
The Current Maintainer of this work is Yossi Gil. 
This work consists of the files \texttt{\me.tex} and \texttt{\me.sty} 
  and the derived file
  \texttt{\me.pdf}
}}

\author{Yossi Gil\thanks{\url{mailto:yogi@cs.Technion.ac.IL}}\\
   \normalsize Department of Computer Science\\
   \normalsize The Technion---Israel Institute of Technology\\
   \normalsize Technion City, Haifa 32000, Israel
}

\makeatletter
\date{\date@bashful\thanks{
      This document describes \bashful \version@bashful.}}
\makeatother

\begin{document}
\bash
cat << EOF > README
The bashful package, v 0.91

This package makes it possible to execute bash scripts from within LaTeX. The
main application is in writing computer-science texts, in which you want to
make sure the programs listed in the document are executed directly from the
input. 

This package may be distributed and/or modified under the LaTeX Project Public
License, version 1.3 or higher (your choice). The latest version of this
license is at: http://www.latex-project.org/lppl.txt

This work is author-maintained (as per LPPL maintenance status)
by Yossi Gil, <yogi@cs.Technion.ac.i>
EOF
\END

\maketitle

\begin{abstract}
\parindent 1.5ex
\parskip 0.5em

\sl
It is sometimes useful to ``\emph{escape-to-shell}'' from within
	\LaTeX{}. 
The most obvious application is when the document
	explains something about the working of a computer program.
Your text would be more robust to changes, and easier to write,
	if all the examples it gives, are run directly from
	within \LaTeX{}.
	
To facilitate this and other applications, 
  package \bashful{} provides a convenient interface to \TeX's 
	primitive \verb+\write18+---the execution of shell commands from within
	your input files, also known as \emph{shell escape}. 
Text between \verb+\bash+ and \verb+\END+ is executed by 
	the \href
	      {http://en.wikipedia.org/wiki/Bash_%28Unix_shell%29}
	      {\texttt{bash}},
	a popular Unix command line interpreter.
Various flags control whether the executed commands and their output 
	show up in the printed document, and whether they are saved
	to files. 

Although provisions are made for using shells other 
	than \texttt{bash}, this package may \emph{not} operate without
	modifications on  Microsoft's operating systems.
\end{abstract}
\eject

\tableofcontents

\parindent 1.5ex
\parskip 0.5em

\section{Introduction}
\bash[verbose]
rm -f temperature.tex
rm -f condition.tex
\END

\bash[verbose,scriptFile=temperature.sh,stdoutFile=temperature.tex]
location=Jerusalem,Israel
server="http://www.Google.com/ig/api"
request="$server?weather=$location" 
wget -q -O - $request |\
tr "<>" "\012\012" |\
grep temp_c |\
sed 's/[^0-9]//g'
\END

\bash[verbose,scriptFile=condition.sh,stdoutFile=condition.tex]
location=Jerusalem,Israel
server="http://www.Google.com/ig/api"
request="$server?weather=$location" 
wget -q -O - $request |\
tr "<>" "\012\012" |\
grep "condition data" |\
head -n 1 |\ 
sed -e 's/^.*="//' -e 's/"\/*//' |\
tr 'A-Z' 'a-z'
\END

At the time I run this document through \LaTeX{}, 
	the temperature in Jerusalem, Israel, 
	was~\emph{\input{temperature.tex}\celsius}, 
	while the weather condition was \emph{\input{condition}}\unskip.
	
You may not care so much about these bits of truly
  ephemeral information,
	but you may be surprised that they were produced 
	by the very process of \LaTeX{}ing. 

How did I do that? Well, the first step was to write 
	a series of shell commands that retrieve the current temperature,
	and another such series to obtain the current 
	weather conditions.  
This task required connection to 
\href{http://www.Google.com/support/forum/p/apps-apis/thread?tid=0c95e45bd80def1a&hl=en}%
{Google's weather service} and 
	minimal dexterity with Unix pipes and filters to process the output.
My command series to obtain the current temperature was:
 
\begin{minipage}{\textwidth}
\begin{quote}
	\lstinputlisting[style=input]{temperature.sh}
\end{quote}
\end{minipage}

while the weather condition was obtained by 

\begin{minipage}{\textwidth}
\begin{quote}
	\lstinputlisting[style=input]{condition.sh}
\end{quote}
\end{minipage}

The second step was coercing \LaTeX{} to run these commands
  while processing this file.	
To do that, I wrapped these two series within 
	a \verb+\bash+\ldots\verb+\END+ pair.
The \verb+\bash+ command, offered by this package,
	takes all subsequent lines, stopping at  the closing \verb+\END+,
	places these in a file, and then 
	lets the \texttt{bash} shell interpreter execute this file.

Allowing \LaTeX{} to run arbitrary shell commands can be 
	dangerous---you never know whether that nice looking \texttt{tex}
	file you received by email was prepared by a friend or 
	a foe.
This is the reason that you have to tell \LaTeX{} 
	explicitly that shell escapes 
	are allowed. 
The \texttt{-shell-esc} does that.
Processing this file was thus done by executing, at the command line,
\begin{quote}
	\tt
	\% latex -shell-escape \jobname.tex
\end{quote}

What I actually wrote in my \texttt{.tex} file 
  to produce the temperature in 
	Jerusalem, Israel was: 
	
\begin{minipage}{\textwidth}
\begin{quote}
\noindent\verb+\bash[verbose,scriptFile=temperature.sh,stdoutFile=temperature.tex]+
\lstinputlisting[style=input]{temperature.sh}
\verb+\END+\\
\end{quote}
\end{minipage}

The flags passed to above to the \verb+bash+ control sequence instructed it:
	\begin{enumerate}
		\item to be verbose, typing out a detailed log of everything it did;
		\item to save the shell commands in a script file named 
		      \texttt{temperature.sh}; and,
		\item to store the standard output of the script in a file named 
		      \texttt{temperature.tex}. 
	\end{enumerate}

To obtain the current weather condition in the capital I wrote: 


\begin{minipage}{\textwidth}
\begin{quote}
\noindent\verb+\bash[verbose,scriptFile=condition.sh,stdoutFile=condition.tex]+
\lstinputlisting[style=input]{condition.sh}
\verb+\END+
\end{quote}
\end{minipage}

I wrote these two just after my \verb+\begin{document}+. 
When \LaTeX{} encountered these, it executed the bash commands and 
	created two files \texttt{temperature.tex} and \texttt{condition.tex}.

Subsequently, I could use the content of these files by writing:


\begin{quote}
\begin{verbatim}
At the time I run this document through \LaTeX{}, 
	the temperature in Jerusalem, Israel, 
	was~\emph{\input{temperature.tex}\celsius}, 
	while the weather condition was \emph{\input{condition}}\unskip.
\end{verbatim}
\end{quote}

\section{An Easy to Digest Example}
If you were intimidated by technicalities of the
  above description, let's try another example
  that might be easier to digest.
  
I will start by telling a simple story
  of writing, compiling and executing and 
    a simple program.
Then, I will explain how I used the \verb+\bash+
  command to not only tell a story, but
  also to play it live: that is, authoring
  a simple~C program, compiling it and executing
  it, all from within \LaTeX{}.
  
\subsection{A ``Hello, World'' Program} 
 
\subsubsection{Authoring}
Let's first write a simple 
  \href{http://en.wikipedia.org/wiki/Hello_world_program}
    {Hello, World!} program in the 
    \href{http://en.wikipedia.org/wiki/C_(programming_language)}
    {C programming language}:

\begin{quote}
\bash[verbose,list]
rm -f hello.c; cat << EOF > hello.c
/* 
** hello.c: My first C program; it prints 
** "Hello, World!", and dies.
*/

#include <stdio.h> 

int main() 
{
  printf("Hello, World!\n");
  return 0;
}
EOF
\END
\end{quote}

\subsubsection{Compiling}
Now, let's compile this program:
\begin{quote}
\bash[list,stdout]
cc hello.c
\END
\end{quote}

\subsubsection{Executing}
Finally, we can execute this program,
  and see that indeed, it prints the ``Hello, World!''
  string.
\begin{quote}
\bash[list,stdout]
./a.out
\END
\end{quote}

\subsection{Behind the Scenes}
\subsubsection{Authoring}
What I wrote in the input to produce the 
  \texttt{hello.c} program was:
\begin{quote}
\begin{verbatim}
\bash[list]
rm -f hello.c; cat << EOF > hello.c
/* 
** hello.c: My first C program; it prints 
** "Hello, World!", and dies.
*/

#include <stdio.h> 

int main() 
{
  printf("Hello, World!\n");
  return 0;
}
EOF
\END
\end{verbatim}
\end{quote}

In doing so, all the text between the \verb+\bash+
  and \verb+\END+ was sent to a temporary file,
    which was then sent to the \texttt{bash}
    bash shell for execution.
The \texttt{list} flag instructed \verb+\bash+
  to list this file in the main document.
This listing was prefixed with \verb*+% +
  to make it clear that it was input to \texttt{bash}.
 
\subsubsection{Compiling} 
Next, I wrote
\begin{quote}
\begin{verbatim}
\bash[list]
cc hello.c
\END
\end{verbatim}
\end{quote}

As before, in doing that, I achieved two objectives:
  first, when \LaTeX{} processed
  the input, it also invokes the~C compiler to compile
  file \texttt{hello.c}, the file which I just created.
Second, thanks to the \texttt{list} flag,
  the command for compiling this program
  was included in the printed version of 
  this document.
Thanks to the \texttt{stdout} option, 
 plain messages, i.e., not error messages,
 produced by the compiler would show on 
  the printed version of this document.
In this case, no such messages were produced.


\subsubsection{Executing}

Finally, I wrote 
\begin{quote}
\begin{verbatim}
\bash[list,stdout]
./a.out
\END
\end{verbatim}
\end{quote}
to run the program I just wrote.
The \texttt{stdout} adds to my listing
  the output that this execution produces, i.e.,
  the string \texttt{Hello, World!} that this
  execution produces to the standard output.
  
\section{Dealing with Shell Command Errors}
Using \bashful{} to demonstrate
  my \emph{Hello, World!} program, made
  sure that the story I told is accurate:
I really did everything I said I did.
More accurately, the \verb+\bash+ command
  acted as my proxy, and did it for me.
  
Luckily, my \texttt{hello.c} program was 
  correct.
But, if it was not, the \verb+\bash+ command would have detected
  the error, and would have stopped the \LaTeX{} process, 
  indicating that the compilation did not succeed.
More specifically, the \verb+\bash+ command 
\begin{enumerate}
\item collects all commands up to \verb+\END+; 
\item places these commands in a script file; 
\item executes this script file, redirecting its standard output
      and its standard error streams to distinct files; 
\item checks whether the exit code of the execution indicates an error
  (i.e., exit code which is different from~$0$), and if so,
    appends this exit code to the file containing the standard error;
\item checks whether the file containing the standard error is empty,
    and if not, pauses execution after displaying an error message;
\item lists, if requested to, the script file; and,
\item lists, if requested to, the file containing the standard output.
\end{enumerate}

Let me demonstrate a situation in which the execution of 
  the script generates an error.
To do that, I will write a short \LaTeX{} file, named \texttt{minimal.tex}
  which tries to use \verb+\bash+ to compile an incorrect~C program.
Since \texttt{minimal.tex} contains \verb+\END+,
  I will have to author this file in three steps:
\begin{enumerate}
\item Creating the header of \texttt{minimal.tex}:
\bash[list]
cat << EOF > minimal.tex
\documentclass{minimal}
\usepackage{bashful}
\begin{document}
\bash
echo "main(){return int;}" > error.c
cc error.c
EOF
\END
\item Adding \verb+\END+ to \texttt{minimal.tex}
\bash[list]
echo "\\END" >> minimal.tex
\END
\item Finalizing \texttt{minimal.tex}
\bash[list]
echo "\\end{document}" >> minimal.tex
\END
\end{enumerate}

Let me now make sure \texttt{minimal.tex} was what I expect it to be:

\begin{minipage}{\textwidth}
\bash[list,stdout]
cat minimal.tex
\END
\end{minipage}

I am now ready to run \texttt{minimal.tex} through \LaTeX{},
  but since I will not run the \texttt{latex} command myself,
  I will make sure a \texttt{q} character is sent to it
  when the anticipated error occurs. 
 
\begin{minipage}{\textwidth}
  \lstdefinestyle{bashfulStdoutFile}{
    showstringspaces=false,
    basicstyle=\scriptsize\ttfamily,
  }%
\bash[list,stdout]
yes x | latex -shell-esc minimal.tex
\END
\end{minipage}

You can see that when \LaTeX{} tried to process \texttt{minimal.tex},
  it stopped execution while indicating that file
  \texttt{minimal.stderr} was not 
  empty after the compilation. The first line of \texttt{minimal.stderr}
  was displayed, and I was advised to examine this file myself.
Inspecting \texttt{minimal.stderr}, we see the C compiler error messages:

\begin{minipage}{\textwidth}
\bash[list,stdout]
cat minimal.stderr
\END
\end{minipage}
  
\section{Customization}

\subsection{Options}

Options to \verb+\bash+ are passed using the \textsf{xkeyval} syntax:

\newcommand\option[3]{%
      \noindent\(
          \text{\bfseries\texttt{#1}}
          =
          \langle\text{{#2}}\rangle
      \)
      \hfill\texttt{#3}\\}
      

\option{scriptFile}{\sl fileName}{\textbackslash jobname.sh}
Name of file into which the script instructions are spilled prior 
  to execution.
The default is \verb+\jobname.sh+; this file
  will be reused by all \verb+\bash+ commands in your documents.
  This is rarely a problem, since these scripts
  execute sequentially.

\option{stdoutFile}{\sl fileName}{\textbackslash jobname.stdout}
Name of file into which the shell standard output stream is 
  redirected. 
  

\option{stderrFile}{\sl fileName}{\textbackslash jobname.stderr}
Name of file into which the shell standard error stream is 
  redirected. 

\option{list}{\texttt{true}/\texttt{false}}{\texttt{false}}
If \texttt{true}, the content of \texttt{scriptFile} 
  is listed in the main document.

\option{stdout}{\texttt{true}/\texttt{false}}{\texttt{false}}
If \texttt{true}, the content of \texttt{stdoutFile} 
  is listed in the main document.
If both \texttt{list} and \texttt{stdout} are 
  \texttt{true}, then \texttt{scriptFile} is listed
  first, and leaving no vertical space, 
  \texttt{stdoutFile} is listed next.
  
\option{prefix}{tokens}{\percentchar\textvisiblespace}
String that prefixes the listing of \texttt{scriptFile}. 

\option{verbose}{\texttt{true}/\texttt{false}}{\texttt{false}}
If \texttt{true}, the package logs every step it takes.

\subsection{Listings Styles}
Package 
  \href
    {ftp://ftp.tex.ac.uk/tex-archive/macros/latex/contrib/listings/listings.pdf}
    {\textsf{listing}}
  is used for all listing both the executed shell
  commands and their output.
\subsubsection{Listings Style for Script File}

Style \verb+bashfulList+ is used for displaying the executed shell
  commands (when option \texttt{list} is used).
The current definition of this style is:
\begin{verbatim}
\lstdefinestyle{bashfulList}{
    basicstyle=\ttfamily,
    showstringspaces=false}
\end{verbatim}
Redefine this style to match your needs.

\subsubsection{Listings Style for Standard Output}

Style \verb+bashfulStdout+ is used for displaying the output of the 
  executed shell
  commands (when option \texttt{stdout} is used).
The current definition is:
\begin{verbatim}
  \lstdefinestyle{bashfulStdout}{
    basicstyle=\sl\ttfamily,
    showstringspaces=false
  }
\end{verbatim}
Redefine this style to match your needs.

\section{Interaction with Other Packages}
This packages tries to work around a bug in \texttt{polyglossia}
  by which \verb+\texttt+ is garbled upon 
  switching to languages which do not use the Latin alphabet.
Also, in case bidirectional \TeX{}ing is in effect,
  \bashful forces the listing to be left-to-right.


\section{History}
\begin{description}
\item[Version 0.91] Initial release
\end{description}

\section{Future}
The following may get implemented some day.

\begin{enumerate}
\item \emph{Package options.} Currently all options are 
    passed to the command itself.
\item \emph{A \texttt{clean} option.} This option
  will automatically erase files
  generated for storing the script, and its standard
  output and standard error streams.
  
\item \emph{A \texttt{noclobber} option.} This option
  will make this package safer, by reducing the risk
  of accidentally erasing existing files.
  
  
\item \emph{A \texttt{ignoreExitCode} option.} When
  \texttt{true} \verb+\bash+ will consider
    an execution correct even if its exit code
    is not 0.
    
\item \emph{A \texttt{ignoreStderr} option.} When
  \texttt{true} \verb+\bash+ will consider
    an execution correct even if produces
    output to the standard error stream.
\end{enumerate}

\section{Acknowledgments}
The manner by which \verb+\bash+ 
  collects its arguments is based on that of
 \href
  {http://www.tn-home.de/Tobias/Soft/TeX/tobiShell.pdf}
  {\textsf{tobiShell}}.
Martin Scharrer tips on \TeX{} internals
  were invaluable.

\appendix
\section{Source of \texttt{\jobname.sty}}
	\lstinputlisting
	  [		style=input,
				basicstyle=\scriptsize\ttfamily,
				numbers=left,
				stepnumber=10,
				numberstyle=\scriptsize\rmfamily\bfseries
		]
	  {\jobname.sty}
	
\section{Source of the Current Document}
	\lstinputlisting
	  [		style=input,
				basicstyle=\scriptsize\ttfamily,
				numbers=left,
				stepnumber=10,
				numberstyle=\scriptsize\rmfamily\bfseries
		]
	  {\jobname.tex}


\end{document}
