mention that TEXMFHOME, et al., can be multiple directories via brace expansion

git-svn-id: svn://tug.org/texlive/trunk@20605 c570f23f-e606-0410-a88d-b1316a301751

1 files changed, 27 insertions, 6 deletions

diff --git a/Master/texmf/doc/texlive/texlive-en/texlive-en.tex b/Master/texmf/doc/texlive/texlive-en/texlive-en.tex
index c72cb58b17b..3642b1f076d 100644
--- a/Master/texmf/doc/texlive/texlive-en/texlive-en.tex
+++ b/Master/texmf/doc/texlive/texlive-en/texlive-en.tex
@@ -20,7 +20,7 @@
         \url{http://tug.org/texlive/}
        }
 
-\date{July 2010}
+\date{November 2010}
 
 \maketitle
 
@@ -53,6 +53,7 @@ For a brief summary of the major changes in this edition of \TL{},
 see the end of the document, section~\ref{sec:history}
 (\p.\pageref{sec:history}).
 
+
 \subsection{Operating system support}
 \label{sec:os-support}
 
@@ -351,6 +352,11 @@ The default layout is:
   \end{ttdescription}
 \end{description}
 
+All of the trees, including the personal ones, should follow the \TeX\
+Directory Structure (\TDS), with all its myriad subdirectories, or files
+may not be found.  Section \ref{sec:local-personal-macros}
+(\p.\pageref{sec:local-personal-macros}) describes this in more detail.
+
 
 \subsection{Extensions to \protect\TeX}
 \label{sec:tex-extensions}
@@ -1074,7 +1080,7 @@ For more information, see
 This is already mentioned implicitly in section~\ref{sec:texmftrees}:
 \dirname{TEXMFLOCAL} (by default,
 \dirname{/usr/local/texlive/texmf-local} or
-\verb|%SystemDrive%\texlive\texmf-local|)
+\verb|%SystemDrive%\texlive\texmf-local| on Windows)
 is intended for system-wide local fonts and macros; and
 \dirname{TEXMFHOME} (by default, \dirname{$HOME/texmf} or
 \verb|%USERPROFILE%\texmf|), is for personal fonts and macros.  These
@@ -1084,8 +1090,8 @@ Therefore, it is best to refrain from changing the definition of
 \dirname{TEXMFLOCAL} to be too far away from the main \TL{} directory,
 or you will need to manually change future releases.
 
-For both trees, files should be placed in their proper subdirectories;
-see \url{http://tug.org/tds} or consult
+For both trees, files should be placed in their proper \TeX\ Directory
+Structure (\TDS) subdirectories; see \url{http://tug.org/tds} or consult
 \filename{texmf/web2c/texmf.cnf}. For instance, a \LaTeX{} class file or
 package should be placed in \dirname{TEXMFLOCAL/tex/latex} or
 \dirname{TEXMFHOME/tex/latex}, or a subdirectory thereof.
@@ -1095,6 +1101,20 @@ will not be found.  You can update it with the command
 \cmdname{mktexlsr} or use the `Reinit file database' button on the
 configuration tab of the \TeX\ Live Manager \GUI.
 
+By default, each of these variables is defined to be a single directory,
+as shown.  This is not a hard-and-fast requirement.  If you need to
+easily switch back and forth between different versions of large
+packages, for example, you can maintain multiple trees for your own
+purposes.  This is done by setting \dirname{TEXMFHOME} to the
+list of directories, within braces, separated by commas:
+
+\begin{verbatim}
+  TEXMFHOME = {/my/dir1,/mydir2,/a/third/dir}
+\end{verbatim}
+
+Section~\ref{sec:brace-expansion} describes brace expansion further.
+
+
 \subsubsection{Integrating third-party fonts}
 
 This is unfortunately a messy topic.  Forget about it unless you want to
@@ -1872,13 +1892,14 @@ place.  It checks first for a leading \samp{:}, then a trailing
 \samp{:}, then a doubled \samp{:}.
 
 \subsubsection{Brace expansion}
+\label{sec:brace-expansion}
 
 A useful feature is brace expansion, which means that, for instance,
 \verb+v{a,b}w+ expands to \verb+vaw:vbw+. Nesting is allowed.
 This is used to implement multiple \TeX{} hierarchies, by
 assigning a brace list to \code{\$TEXMF}.
-For example, in \file{texmf.cnf}, the following definition
-(approximately; there are actually even more trees) is made:
+For example, in \file{texmf.cnf}, a definition like this
+(simplified for this example) is made:
 \begin{verbatim}
   TEXMF = {$TEXMFHOME,$TEXMFLOCAL,!!$TEXMFVAR,!!$TEXMFMAIN}
 \end{verbatim}