X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=doc%2Fcombining.texi;h=da0a5ea999d522e2fbf399e42d6ac07e96374472;hb=1809d8a36b646c00093c7c2b51f41441f5441f12;hp=3b4eb902e049eeae669752b7a5cd2c6299d70b96;hpb=e8b26fb0d765310d4c7400c39465008f1bb8601d;p=pspp

diff --git a/doc/combining.texi b/doc/combining.texi
index 3b4eb902e0..da0a5ea999 100644
--- a/doc/combining.texi
+++ b/doc/combining.texi
@@ -58,9 +58,11 @@ This section describes the syntactical features in common among the
 @cmd{ADD FILES}, @cmd{MATCH FILES}, and @cmd{UPDATE} commands.  The
 following sections describe details specific to each command.
 
-Each of these commands reads two or more input files and combines
-them.  The command's output becomes the new active dataset.  The input
-files are not changed on disk.
+Each of these commands reads two or more input files and combines them.  
+The command's output becomes the new active dataset.
+None of the commands actually change the input files.
+Therefore, if you want the changes to become permanent, you must explicitly
+save them using an appropriate procedure or transformation (@pxref{System and Portable File IO}).
 
 The syntax of each command begins with a specification of the files to
 be read as input.  For each input file, specify FILE with a system
@@ -168,6 +170,9 @@ only in files that are not present for the current case are set to the
 system-missing value for numeric variables or spaces for string
 variables.
 
+These commands may combine any number of files, limited only by the
+machine's memory.
+
 @node ADD FILES
 @section ADD FILES
 @vindex ADD FILES
@@ -315,14 +320,14 @@ case in the master file:
 @itemize @bullet
 @item
 When a match is found, then the values of the variables present in the
-transaction file replace those variable's values in the new active
+transaction file replace those variables' values in the new active
 file.  If there are matching cases in more than more transaction file,
 @pspp{} applies the replacements from the first transaction file, then
 from the second transaction file, and so on.  Similarly, if a single
 transaction file has cases with duplicate @subcmd{BY} values, then those are
 applied in order to the master file.
 
-When a variable in a transaction file has a missing value or a string
+When a variable in a transaction file has a missing value or when a string
 variable's value is all blanks, that value is never used to update the
 master file.