Added information on how input and output files are selected.
Added information on where files are located by llvm-link.
Added missing options.
Re-worded some stuff so that it (hopefully) sounds better.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@8723 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/docs/CommandGuide/opt.html b/docs/CommandGuide/opt.html
index cab5946..52b1683 100644
--- a/docs/CommandGuide/opt.html
+++ b/docs/CommandGuide/opt.html
@@ -20,19 +20,27 @@
 SYNOPSIS
 </h3>
 
-opt [options] &lt; filename&gt;
+opt [options] [filename]
 <h3>
 DESCRIPTION
 </h3>
 
 The opt command is the LLVM optimizer.  It takes LLVM bytecode as input, runs
-the specified optimizations on it, and then outputs the optimized code in LLVM
+the specified optimizations on it, and then outputs the optimized LLVM
 bytecode.
+<p>
 
-The optimizations available via opt depend upon what libraries it was linked
-with, as well as any additional libraries that have been loaded with the -load
-option.  Use the -help option to determine what optimizations you can use.
+The optimizations available via opt depend upon what libraries were linked
+into it as well as any additional libraries that have been loaded with the
+-load option.  Use the -help option to determine what optimizations you can use.
+<p>
 
+If no filename is specified on the command line, opt reads its input from
+standard input.
+<p>
+
+If an output filename is not specified with the -o option, opt writes its
+output to the standard output.
 <h3>
 OPTIONS
 </h3>