zgrep: usage should say which grep options are not supported

* zgrep.in (usage): Document which grep options are not supported.
Problem reported by Liron Paryente in
<http://lists.gnu.org/archive/html/bug-grep/2013-06/msg00005.html>.

diff --git a/zgrep.in b/zgrep.in
index 154d17f4cea73a20179fdcb86a014fc670a9a465..c149577c57b417994d791a744037366e4eba4a65 100644 (file)
--- a/zgrep.in
+++ b/zgrep.in
@@ -42,7 +42,10 @@ usage="Usage: $0 [OPTION]... [-e] PATTERN [FILE]...
 Look for instances of PATTERN in the input FILEs, using their
 uncompressed contents if they are compressed.
 
 Look for instances of PATTERN in the input FILEs, using their
 uncompressed contents if they are compressed.
 

-OPTIONs are the same as for 'grep'.
+OPTIONs are the same as for 'grep', except that the following 'grep'
+options are not supported: --dereference-recursive (-R), --directories (-d),
+--exclude, --exclude-from, --exclude-dir, --include, --null (-Z),
+--null-data (-z), and --recursive (-r).

 
 Report bugs to <bug-gzip@gnu.org>."
 
 
 Report bugs to <bug-gzip@gnu.org>."