Give another example of binary file processing

Problem reported by Shlomi Fish
* doc/grep.texi (File and Directory Selection):
Document that 'q$' might match 'q' followed by a NUL
if --binary-files=binary is in effect.

1 files changed, 10 insertions, 4 deletions

diff --git a/doc/grep.texi b/doc/grep.texi
index 074113b7..1d3d5cb0 100644
--- a/doc/grep.texi
+++ b/doc/grep.texi
@@ -607,10 +607,6 @@ By default, @var{type} is @samp{binary}, and when @command{grep}
 discovers that a file is binary it suppresses any further output, and
 instead outputs either a one-line message saying that a binary file
 matches, or no message if there is no match.
-When processing binary data, @command{grep} may treat non-text bytes
-as line terminators; for example, the pattern @samp{.} (period) might
-not match a null byte, as the null byte might be treated as a line
-terminator even without the @option{-z} (@option{--null-data}) option.
 
 If @var{type} is @samp{without-match},
 when @command{grep} discovers that a file is binary
@@ -621,6 +617,16 @@ If @var{type} is @samp{text},
 @command{grep} processes a binary file as if it were text;
 this is equivalent to the @option{-a} option.
 
+When @var{type} is @samp{binary}, @command{grep} may treat non-text
+bytes as line terminators even without the @option{-z}
+(@option{--null-data}) option.  This means choosing @samp{binary}
+versus @samp{text} can affect whether a pattern matches a file.  For
+example, when @var{type} is @samp{binary} the pattern @samp{q$} might
+match @samp{q} immediately followed by a null byte, even though this
+is not matched when @var{type} is @samp{text}.  Conversely, when
+@var{type} is @samp{binary} the pattern @samp{.} (period) might not
+match a null byte.
+
 @emph{Warning:} @samp{--binary-files=text} might output binary garbage,
 which can have nasty side effects
 if the output is a terminal and