X-Git-Url: https://git.tokkee.org/?a=blobdiff_plain;f=Documentation%2Fgitattributes.txt;h=8af22eccac85492416d36259baa60594c9b8382f;hb=5fdb70983585ccde1540563a8c7458621f7a7407;hp=eb648418eedba4f131aec1f18ccba3bd62f53dc2;hpb=aebd173ffa7a4e67447f0157a14abde7767c54e9;p=git.git

diff --git a/Documentation/gitattributes.txt b/Documentation/gitattributes.txt
index eb648418e..8af22ecca 100644
--- a/Documentation/gitattributes.txt
+++ b/Documentation/gitattributes.txt
@@ -216,10 +216,12 @@ Generating diff text
 `diff`
 ^^^^^^
 
-The attribute `diff` affects if 'git-diff' generates textual
-patch for the path or just says `Binary files differ`.  It also
-can affect what line is shown on the hunk header `@@ -k,l +n,m @@`
-line.
+The attribute `diff` affects how 'git' generates diffs for particular
+files. It can tell git whether to generate a textual patch for the path
+or to treat the path as a binary file.  It can also affect what line is
+shown on the hunk header `@@ -k,l +n,m @@` line, tell git to use an
+external command to generate the diff, or ask git to convert binary
+files to a text format before generating the diff.
 
 Set::
 
@@ -230,7 +232,8 @@ Set::
 Unset::
 
 	A path to which the `diff` attribute is unset will
-	generate `Binary files differ`.
+	generate `Binary files differ` (or a binary patch, if
+	binary patches are enabled).
 
 Unspecified::
 
@@ -241,21 +244,21 @@ Unspecified::
 
 String::
 
-	Diff is shown using the specified custom diff driver.
-	The driver program is given its input using the same
-	calling convention as used for GIT_EXTERNAL_DIFF
-	program.  This name is also used for custom hunk header
-	selection.
+	Diff is shown using the specified diff driver.  Each driver may
+	specify one or more options, as described in the following
+	section. The options for the diff driver "foo" are defined
+	by the configuration variables in the "diff.foo" section of the
+	git config file.
 
 
-Defining a custom diff driver
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+Defining an external diff driver
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 The definition of a diff driver is done in `gitconfig`, not
 `gitattributes` file, so strictly speaking this manual page is a
 wrong place to talk about it.  However...
 
-To define a custom diff driver `jcdiff`, add a section to your
+To define an external diff driver `jcdiff`, add a section to your
 `$GIT_DIR/config` file (or `$HOME/.gitconfig` file) like this:
 
 ----------------------------------------------------------------
@@ -331,6 +334,43 @@ patterns are available:
 - `tex` suitable for source code for LaTeX documents.
 
 
+Performing text diffs of binary files
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Sometimes it is desirable to see the diff of a text-converted
+version of some binary files. For example, a word processor
+document can be converted to an ASCII text representation, and
+the diff of the text shown. Even though this conversion loses
+some information, the resulting diff is useful for human
+viewing (but cannot be applied directly).
+
+The `textconv` config option is used to define a program for
+performing such a conversion. The program should take a single
+argument, the name of a file to convert, and produce the
+resulting text on stdout.
+
+For example, to show the diff of the exif information of a
+file instead of the binary information (assuming you have the
+exif tool installed):
+
+------------------------
+[diff "jpg"]
+	textconv = exif
+------------------------
+
+NOTE: The text conversion is generally a one-way conversion;
+in this example, we lose the actual image contents and focus
+just on the text data. This means that diffs generated by
+textconv are _not_ suitable for applying. For this reason,
+only `git diff` and the `git log` family of commands (i.e.,
+log, whatchanged, show) will perform text conversion. `git
+format-patch` will never generate this output. If you want to
+send somebody a text-converted diff of a binary file (e.g.,
+because it quickly conveys the changes you have made), you
+should generate it separately and send it as a comment _in
+addition to_ the usual binary diff that you might send.
+
+
 Performing a three-way merge
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
@@ -495,6 +535,23 @@ in the file.  E.g. the string `$Format:%H$` will be replaced by the
 commit hash.
 
 
+Viewing files in GUI tools
+~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+`encoding`
+^^^^^^^^^^
+
+The value of this attribute specifies the character encoding that should
+be used by GUI tools (e.g. linkgit:gitk[1] and linkgit:git-gui[1]) to
+display the contents of the relevant file. Note that due to performance
+considerations linkgit:gitk[1] does not use this attribute unless you
+manually enable per-file encodings in its options.
+
+If this attribute is not set or has an invalid value, the value of the
+`gui.encoding` configuration variable is used instead
+(See linkgit:git-config[1]).
+
+
 USING ATTRIBUTE MACROS
 ----------------------