<commit_before>Generating patches with -p
--------------------------

When "git-diff-index", "git-diff-tree", or "git-diff-files" are run
with a '-p' option, "git diff" without the '--raw' option, or
"git log" with the "-p" option, they
do not produce the output described above; instead they produce a
patch file.  You can customize the creation of such patches via the
GIT_EXTERNAL_DIFF and the GIT_DIFF_OPTS environment variables.

What the -p option produces is slightly different from the traditional
diff format.

1.   It is preceded with a "git diff" header, that looks like
     this:

       diff --git a/file1 b/file2
+
The `a/` and `b/` filenames are the same unless rename/copy is
involved.  Especially, even for a creation or a deletion,
`/dev/null` is _not_ used in place of `a/` or `b/` filenames.
+
When rename/copy is involved, `file1` and `file2` show the
name of the source file of the rename/copy and the name of
the file that rename/copy produces, respectively.

2.   It is followed by one or more extended header lines:

       old mode <mode>
       new mode <mode>
       deleted file mode <mode>
       new file mode <mode>
       copy from <path>
       copy to <path>
       rename from <path>
       rename to <path>
       similarity index <number>
       dissimilarity index <number>
       index <hash>..<hash> <mode>

3.  TAB, LF, double quote and backslash characters in pathnames
    are represented as `\t`, `\n`, `\"` and `\\`, respectively.
    If there is need for such substitution then the whole
    pathname is put in double quotes.

The similarity index is the percentage of unchanged lines, and
the dissimilarity index is the percentage of changed lines.  It
is a rounded down integer, followed by a percent sign.  The
similarity index value of 100% is thus reserved for two equal
files, while 100% dissimilarity means that no line from the old
file made it into the new one.


combined diff format
--------------------

"git-diff-tree", "git-diff-files" and "git-diff" can take '-c' or
'--cc' option to produce 'combined diff'.  For showing a merge commit
with "git log -p", this is the default format.
A 'combined diff' format looks like this:

------------
diff --combined describe.c
index fabadb8,cc95eb0..4866510
--- a/describe.c
+++ b/describe.c
@@@ -98,20 -98,12 +98,20 @@@
	return (a_date > b_date) ? -1 : (a_date == b_date) ? 0 : 1;
  }

- static void describe(char *arg)
 -static void describe(struct commit *cmit, int last_one)
++static void describe(char *arg, int last_one)
  {
 +	unsigned char sha1[20];
 +	struct commit *cmit;
	struct commit_list *list;
	static int initialized = 0;
	struct commit_name *n;

 +	if (get_sha1(arg, sha1) < 0)
 +		usage(describe_usage);
 +	cmit = lookup_commit_reference(sha1);
 +	if (!cmit)
 +		usage(describe_usage);
 +
	if (!initialized) {
		initialized = 1;
		for_each_ref(get_name);
------------

1.   It is preceded with a "git diff" header, that looks like
     this (when '-c' option is used):

       diff --combined file
+
or like this (when '--cc' option is used):

       diff --c file

2.   It is followed by one or more extended header lines
     (this example shows a merge with two parents):

       index <hash>,<hash>..<hash>
       mode <mode>,<mode>..<mode>
       new file mode <mode>
       deleted file mode <mode>,<mode>
+
The `mode <mode>,<mode>..<mode>` line appears only if at least one of
the <mode> is different from the rest. Extended headers with
information about detected contents movement (renames and
copying detection) are designed to work with diff of two<commit_msg>git-diff(1): "--c" -> "--cc" typo fix<commit_after>Generating patches with -p
--------------------------

When "git-diff-index", "git-diff-tree", or "git-diff-files" are run
with a '-p' option, "git diff" without the '--raw' option, or
"git log" with the "-p" option, they
do not produce the output described above; instead they produce a
patch file.  You can customize the creation of such patches via the
GIT_EXTERNAL_DIFF and the GIT_DIFF_OPTS environment variables.

What the -p option produces is slightly different from the traditional
diff format.

1.   It is preceded with a "git diff" header, that looks like
     this:

       diff --git a/file1 b/file2
+
The `a/` and `b/` filenames are the same unless rename/copy is
involved.  Especially, even for a creation or a deletion,
`/dev/null` is _not_ used in place of `a/` or `b/` filenames.
+
When rename/copy is involved, `file1` and `file2` show the
name of the source file of the rename/copy and the name of
the file that rename/copy produces, respectively.

2.   It is followed by one or more extended header lines:

       old mode <mode>
       new mode <mode>
       deleted file mode <mode>
       new file mode <mode>
       copy from <path>
       copy to <path>
       rename from <path>
       rename to <path>
       similarity index <number>
       dissimilarity index <number>
       index <hash>..<hash> <mode>

3.  TAB, LF, double quote and backslash characters in pathnames
    are represented as `\t`, `\n`, `\"` and `\\`, respectively.
    If there is need for such substitution then the whole
    pathname is put in double quotes.

The similarity index is the percentage of unchanged lines, and
the dissimilarity index is the percentage of changed lines.  It
is a rounded down integer, followed by a percent sign.  The
similarity index value of 100% is thus reserved for two equal
files, while 100% dissimilarity means that no line from the old
file made it into the new one.


combined diff format
--------------------

"git-diff-tree", "git-diff-files" and "git-diff" can take '-c' or
'--cc' option to produce 'combined diff'.  For showing a merge commit
with "git log -p", this is the default format.
A 'combined diff' format looks like this:

------------
diff --combined describe.c
index fabadb8,cc95eb0..4866510
--- a/describe.c
+++ b/describe.c
@@@ -98,20 -98,12 +98,20 @@@
	return (a_date > b_date) ? -1 : (a_date == b_date) ? 0 : 1;
  }

- static void describe(char *arg)
 -static void describe(struct commit *cmit, int last_one)
++static void describe(char *arg, int last_one)
  {
 +	unsigned char sha1[20];
 +	struct commit *cmit;
	struct commit_list *list;
	static int initialized = 0;
	struct commit_name *n;

 +	if (get_sha1(arg, sha1) < 0)
 +		usage(describe_usage);
 +	cmit = lookup_commit_reference(sha1);
 +	if (!cmit)
 +		usage(describe_usage);
 +
	if (!initialized) {
		initialized = 1;
		for_each_ref(get_name);
------------

1.   It is preceded with a "git diff" header, that looks like
     this (when '-c' option is used):

       diff --combined file
+
or like this (when '--cc' option is used):

       diff --cc file

2.   It is followed by one or more extended header lines
     (this example shows a merge with two parents):

       index <hash>,<hash>..<hash>
       mode <mode>,<mode>..<mode>
       new file mode <mode>
       deleted file mode <mode>,<mode>
+
The `mode <mode>,<mode>..<mode>` line appears only if at least one of
the <mode> is different from the rest. Extended headers with
information about detected contents movement (renames and
copying detection) are designed to work with diff of two
{'fraction_non_alphanumeric': 0.11707587737550285, 'fraction_numerical': 0.014010264946594535, 'mean_word_length': 2.9966740576496673, 'pattern_counts': {'":': 0, '<': 57, '<?xml version=': 0, '>': 58, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
{'dir': 'git-commits-cleaned', 'id': '232745', 'n_tokens_mistral': 2310, 'n_tokens_neox': 2207, 'n_words': 983}