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-rw-r--r--Documentation/diff-options.txt38
1 files changed, 30 insertions, 8 deletions
diff --git a/Documentation/diff-options.txt b/Documentation/diff-options.txt
index b8a9b86375..a85288f23e 100644
--- a/Documentation/diff-options.txt
+++ b/Documentation/diff-options.txt
@@ -383,14 +383,36 @@ ifndef::git-format-patch[]
that matches other criteria, nothing is selected.
-S<string>::
- Look for differences that introduce or remove an instance of
- <string>. Note that this is different than the string simply
- appearing in diff output; see the 'pickaxe' entry in
- linkgit:gitdiffcore[7] for more details.
+ Look for differences that change the number of occurrences of
+ the specified string (i.e. addition/deletion) in a file.
+ Intended for the scripter's use.
++
+It is useful when you're looking for an exact block of code (like a
+struct), and want to know the history of that block since it first
+came into being: use the feature iteratively to feed the interesting
+block in the preimage back into `-S`, and keep going until you get the
+very first version of the block.
-G<regex>::
- Look for differences whose added or removed line matches
- the given <regex>.
+ Look for differences whose patch text contains added/removed
+ lines that match <regex>.
++
+To illustrate the difference between `-S<regex> --pickaxe-regex` and
+`-G<regex>`, consider a commit with the following diff in the same
+file:
++
+----
++ return !regexec(regexp, two->ptr, 1, &regmatch, 0);
+...
+- hit = !regexec(regexp, mf2.ptr, 1, &regmatch, 0);
+----
++
+While `git log -G"regexec\(regexp"` will show this commit, `git log
+-S"regexec\(regexp" --pickaxe-regex` will not (because the number of
+occurrences of that string did not change).
++
+See the 'pickaxe' entry in linkgit:gitdiffcore[7] for more
+information.
--pickaxe-all::
When `-S` or `-G` finds a change, show all the changes in that
@@ -398,8 +420,8 @@ ifndef::git-format-patch[]
in <string>.
--pickaxe-regex::
- Make the <string> not a plain string but an extended POSIX
- regex to match.
+ Treat the <string> given to `-S` as an extended POSIX regular
+ expression to match.
endif::git-format-patch[]
-O<orderfile>::