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index 517e1eba3c56907ebcb1d478dceb184e53fceda4..c57460c03dd1512e1e3644d3321e87d38316befe 100644 (file)
GIT_EXTERNAL_DIFF and the GIT_DIFF_OPTS environment variables.
What the -p option produces is slightly different from the traditional
-diff format.
+diff format:
-1. It is preceded with a "git diff" header, that looks like
- this:
+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.
+`/dev/null` is _not_ used in place of the `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
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.
-
++
+File modes are printed as 6-digit octal numbers including the file type
+and file permission bits.
++
+Path names in extended headers do not include the `a/` and `b/` prefixes.
++
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.
++
+The index line includes the SHA-1 checksum before and after the change.
+The <mode> is included if the file mode does not change; otherwise,
+separate lines indicate the old and the new 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.
+
+4. All the `file1` files in the output refer to files before the
+ commit, and all the `file2` files refer to files after the commit.
+ It is incorrect to apply each change to each file sequentially. For
+ example, this patch will swap a and b:
+
+ diff --git a/a b/b
+ rename from a
+ rename to b
+ diff --git a/b b/a
+ rename from b
+ rename to a
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.
+Any diff-generating command can take the `-c` or `--cc` option to
+produce a 'combined diff' when showing a merge. This is the default
+format when showing merges with linkgit:git-diff[1] or
+linkgit:git-show[1]. Note also that you can give the `-m' option to any
+of these commands to force generation of diffs with individual parents
+of a merge.
+
A 'combined diff' format looks like this:
------------
A `-` character in the column N means that the line appears in
fileN but it does not appear in the result. A `+` character
-in the column N means that the line appears in the last file,
+in the column N means that the line appears in the result,
and fileN does not have that line (in other words, the line was
added, from the point of view of that parent).
In the above example output, the function signature was changed
from both files (hence two `-` removals from both file1 and
file2, plus `++` to mean one line that was added does not appear
-in either file1 nor file2). Also two other lines are the same
-from file1 but do not appear in file2 (hence prefixed with ` +`).
+in either file1 nor file2). Also eight other lines are the same
+from file1 but do not appear in file2 (hence prefixed with `{plus}`).
When shown by `git diff-tree -c`, it compares the parents of a
merge commit with the merge result (i.e. file1..fileN are the