grep: -r with no args now searches "."

This is a patch I've been meaning to put in for years.
When I added support for "grep -r", I forgot to have "grep -r PAT"
search the working directory by default, instead of searching
standard input (which makes no sense, even if stdin is a directory).
This is not an upward compatible change, since "grep -r PAT <file"
will no longer search standard input, but that's OK; nobody should
be using "grep -r" that way anyway.
* NEWS: Document this.
* doc/grep.texi (File and Directory Selection, grep Programs, Usage):
Likewise.
* src/main.c (usage): Likewise.
(grepdir): If DIR is null, search the working directory, but do
not prepend "./" to the file names.
(main): If recursing and no operands are given, search ".".
* tests/Makefile.am (TESTS): Add r-dot.
* tests/r-dot: New file.

1 files changed, 3 insertions, 0 deletions

diff --git a/NEWS b/NEWS
index d4475bcb..9efb82ab 100644
--- a/NEWS
+++ b/NEWS
@@ -35,6 +35,9 @@ GNU grep NEWS                                    -*- outline -*-
 
 ** New features
 
+  If no file operand is given, grep -r now searches the working directory.
+  Formerly it ignored the -r and searched standard input nonrecursively.
+
   grep now supports color highlighting of matches on MS-Windows.
 
 * Noteworthy changes in release 2.10 (2011-11-16) [stable]