[PATCH] document the core-dump-to-a-pipe patch

The pipe-a-coredump-to-a-program feature was undocumented.
*Grumble*.

NB: a good enhancement to that patch would be: save all the stuff that a
core file can get from the %x expansions in the environment.
Signed-off-by: Matthias Urlichs <matthias@urlichs.de>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Documentation/sysctl/kernel.txt

@@ -86,7 +86,7 @@ valid for 30 seconds.
 core_pattern:
 
 core_pattern is used to specify a core dumpfile pattern name.
-. max length 64 characters; default value is "core"
+. max length 128 characters; default value is "core"
 . core_pattern is used as a pattern template for the output filename;
   certain string patterns (beginning with '%') are substituted with
   their actual values.
@@ -105,6 +105,9 @@ core_pattern is used to specify a core dumpfile pattern name.
 	%h	hostname
 	%e	executable filename
 	%<OTHER> both are dropped
+. If the first character of the pattern is a '|', the kernel will treat
+  the rest of the pattern as a command to run.  The core dump will be
+  written to the standard input of that program instead of to a file.
 
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