[Patch] Make GNU-diff context header more readable. A simple patch to get rid of the \tab in the diff header and aligning the '+++' and '---' lines on the timestamp. Thus making it more readable to see which file is newer or older.

context.diff

--- a/src/context.c 2015-03-09 22:54:10
+++ b/context.c     2015-10-12 21:21:56
@@ -41,7 +41,8 @@
 print_context_label (char const *mark,
 		     struct file_data *inf,
 		     char const *name,
-		     char const *label)
+		     char const *label,
+		     int alignment)
 {
   if (label)
     fprintf (outfile, "%s %s\n", mark, label);
@@ -71,7 +72,7 @@
 	      sprintf (buf, "%"PRIuMAX".%.9d", sec, nsec);
 	    }
 	}
-    fprintf (outfile, "%s %s\t%s\n", mark, name, buf);
+    fprintf (outfile, "%s %s %*s%s\n", mark, name, alignment, "", buf);
     }
 }

@@ -80,16 +81,40 @@
 void
 print_context_header (struct file_data inf[], char const *const *names, bool unidiff)
 {
+  size_t len0 = strlen(names[0]) + (file_label[0] ? strlen(file_label[0]) : 0);
+  size_t len1 = strlen(names[1]) + (file_label[1] ? strlen(file_label[1]) : 0);
+  int align = 1;
+
   if (unidiff)
     {
-      print_context_label ("---", &inf[0], names[0], file_label[0]);
-      print_context_label ("+++", &inf[1], names[1], file_label[1]);
+      if (len0 >= len1)
+        align = 0;
+      else
+        align = len1 - len0;
+      print_context_label ("---", &inf[0], names[0], file_label[0], align);
+
+      if (len1 >= len0)
+        align = 0;
+      else
+        align = len0 - len1;
+      print_context_label ("+++", &inf[1], names[1], file_label[1], align);
     }
   else
     {
-      print_context_label ("***", &inf[0], names[0], file_label[0]);
-      print_context_label ("---", &inf[1], names[1], file_label[1]);
+      if (len0 >= len1)
+        align = 0;
+      else
+        align = len1 - len0;
+      print_context_label ("***", &inf[0], names[0], file_label[0], align);
+
+      if (len1 >= len0)
+        align = 0;
+      else
+        align = len0 - len1;
+      print_context_label ("---", &inf[1], names[1], file_label[1], align);
     }
 }

More description here. The GNU-diff header typically looks like (with the unified option; -u3):

--- a/src/context.c \t 2015-03-09 22:54:10
+++ b/context.c \t 2015-10-12 21:21:56
@@ -41,7 +41,8 @@
...

The \t in the output is an Tabulator (ASCII 9, visible in some editors as 📑, ➡️ or whatever).

Depending on your terminal or editor and it's settings, it can be a pain to quickly see which of the 2 file-timestamps are oldest or newest. The context.diff was meant to fix that. See the 2 first lines above to see the improvement.

You'll need to apply the .diff and rebuild GNU-diff yourself. Good luck.