What is the format of a patch file?

Question

What does the following mean ?

diff -rBNu src.orig/java/org/apache/nutch/analysis/NutchAnalysisConstants.java src/java/org/apache/nutch/analysis/NutchAnalysi         


        

Answer 1

The old file name

--- src.orig/java/org/apache/nutch/analysis/NutchAnalysisConstants.java 2009-03-10 11:34:01.000000000 -0700

The new file name

+++ src/java/org/apache/nutch/analysis/NutchAnalysisConstants.java  2009-03-10 14:11:55.000000000 -0700

• -4: chunk begins at line 4 in old file (including context lines);
• 9: number of lines in the chunk in old file including context lines (so total of lines that have a - or nothing in front of them);
• +4: chunk begins at line 4 in the new file;
• 12: number of lines in the chunk in new file including context lines (so total of lines that have a + or nothing in front of them).

Notice: I changed the diff to include a modified line, so a deleted line followed by an added line.

@@ -4,9 +4,12 @@

+  int CJK = 21;
+  int DIGIT = 22;

-  int DEFAULT = 0;
+  int DEFAULT = 42;

   String[] tokenImage = {
     "",
+    "\"OR\"",
     "",
     "",
     "",

Same as above, but notice the chunk in the new file starts 3 lines further because the previous chunk added a net worth of 3 lines.

@@ -39,6 +42,8 @@
     "\"\\\"\"",
     "\":\"",
     "\"/\"",
+    "\"(\"",
+    "\")\"",
     "\".\"",
     "\"@\"",
     "\"\\\'\"",