Example using Git attributes to make human-friendly output from custom file formats

.gitattributes

bagit.xml diff=xml2rfc

.gitconfig

[diff "xml2rfc"]
    textconv = xml2rfc --quiet --out=/dev/stdout

Example "git log -p" output.diff

commit e6770927bbd594d4a0a3e49dd7b8bc5897e4a394
Author: Chris Adams <cadams@loc.gov>
Date:   Mon Jan 23 10:07:57 2017 -0500

    Update “special directory characters” prose

diff --git a/bagit.xml b/bagit.xml
index 96e466a..8ad9fd6 100644
--- a/bagit.xml
+++ b/bagit.xml
@@ -564,18 +564,20 @@ Internet-Draft                    BagIt                    December 2016
 
 5.1.  Special directory characters
 
-   The paths specified in the payload manifest, and tag manifest file do
-   not prohibit special directory characters which might be significant
-   on implementing systems.  Implementors MUST ensure that files outside
-   the bag directory structure are not accessed when reading or writing
-   files based on paths specified in a bag.
+   The paths specified in the payload manifest and tag manifest file do
+   not prohibit special directory characters which have special meaning
+   on some operating systems.  Implementors MUST ensure that files
+   outside the bag directory structure are not accessed when reading or
+   writing files based on paths specified in a bag.
+
+   All implementations SHOULD have a test suite to guard against these
+   cases.
 
    For example, a maliciously crafted "tagmanifest-md5.txt" file might
    contain entries which begin with a path character such as "/", "..",
    or a "~username" home directory reference in an attempt to cause a
-   naive implementation to leak or overwrite targeted files.  All
-   implementations SHOULD have a test suite to guard against these
-   cases.
+   naive implementation to leak or overwrite targeted files on a POSIX
+   operating system.
 
    Windows implementations SHOULD test their implementations to ensure
    that safety-checks prevent use of drive letters and the less commonly
@@ -608,16 +610,16 @@ Internet-Draft                    BagIt                    December 2016
       multiple files which differ only in case: "example.txt" and
       "Example.txt" are separate files
 
+
+
+
+Boyko, et al.             Expires June 9, 2017                 [Page 11]
+
+Internet-Draft                    BagIt                    December 2016
+
+
    o  NTFS and HFS+ usually preserve case when storing files but are
       case-insensitive when retrieving them.  A file saved as
-
-
-
-Boyko, et al.             Expires June 9, 2017                 [Page 11]
-
-Internet-Draft                    BagIt                    December 2016
-
-
       "Example.txt" will be retrieved by that name but will also be
       retrieved as "EXAMPLE.TXT", "example.txt", etc.
 
@@ -667,8 +669,6 @@ Internet-Draft                    BagIt                    December 2016
 
 
 
-
-
 Boyko, et al.             Expires June 9, 2017                 [Page 12]
 
 Internet-Draft                    BagIt                    December 2016

commit 0257f7bc35bc8e56a990d52e196459b33c66381e
Author: Chris Adams <cadams@loc.gov>
Date:   Mon Jan 23 10:07:37 2017 -0500

    Update “filesystem” reference in “complete” requirements
    
    Since people may wish to use things which aren’t commonly
    considered filesystems (object stores, archive files, etc.)
    this should be more generic.

diff --git a/bagit.xml b/bagit.xml
index a23c515..96e466a 100644
--- a/bagit.xml
+++ b/bagit.xml
@@ -93,7 +93,7 @@ Table of Contents
    3.  Complete, Incomplete, and Valid bags  . . . . . . . . . . . .   9
    4.  Examples  . . . . . . . . . . . . . . . . . . . . . . . . . .  10
      4.1.  Example of a basic bag  . . . . . . . . . . . . . . . . .  10
-   5.  Security Considerations . . . . . . . . . . . . . . . . . . .  11
+   5.  Security Considerations . . . . . . . . . . . . . . . . . . .  10
      5.1.  Special directory characters  . . . . . . . . . . . . . .  11
    6.  Practical Considerations (non-normative)  . . . . . . . . . .  11
      6.1.  Interoperability  . . . . . . . . . . . . . . . . . . . .  11
@@ -506,11 +506,9 @@ Boyko, et al.             Expires June 9, 2017                  [Page 9]
 Internet-Draft                    BagIt                    December 2016
 
 
-   2.  Every file in every tag manifest MUST be present on the
-       filesystem.
+   2.  Every file listed in every tag manifest MUST be present.
 
-   3.  Every file in every payload manifest MUST be present on the
-       filesystem.
+   3.  Every file listed in every payload manifest MUST be present.
 
    4.  Every payload file MUST be listed in every payload manifest.
 
@@ -551,19 +549,19 @@ Internet-Draft                    BagIt                    December 2016
         |    (... OCR text ...                                        )
         ....
 
-
-
-
-
-
-
-Boyko, et al.             Expires June 9, 2017                 [Page 10]
-
-Internet-Draft                    BagIt                    December 2016
-
-
 5.  Security Considerations
 
+
+
+
+
+
+
+Boyko, et al.             Expires June 9, 2017                 [Page 10]
+
+Internet-Draft                    BagIt                    December 2016
+
+
 5.1.  Special directory characters
 
    The paths specified in the payload manifest, and tag manifest file do
@@ -610,16 +608,16 @@ Internet-Draft                    BagIt                    December 2016
       multiple files which differ only in case: "example.txt" and
       "Example.txt" are separate files
 
-
-
-
-Boyko, et al.             Expires June 9, 2017                 [Page 11]
-
-Internet-Draft                    BagIt                    December 2016
-
-
    o  NTFS and HFS+ usually preserve case when storing files but are
       case-insensitive when retrieving them.  A file saved as
+
+
+
+Boyko, et al.             Expires June 9, 2017                 [Page 11]
+
+Internet-Draft                    BagIt                    December 2016
+
+
       "Example.txt" will be retrieved by that name but will also be
       retrieved as "EXAMPLE.TXT", "example.txt", etc.
 
@@ -669,6 +667,8 @@ Internet-Draft                    BagIt                    December 2016
 
 
 
+
+
 Boyko, et al.             Expires June 9, 2017                 [Page 12]
 
 Internet-Draft                    BagIt                    December 2016