* NEWS: New option sort -C, proposed by XCU ERN 127, which looks

like it will be approved.  Also add --check=quiet, --check=silent
as long aliases, and --check=diagnose-first as an alias for -c.
* doc/coreutils.texi (sort invocation): Document this.
Also, mention that sort -c can take at most one file.
* src/sort.c: Implement this.
Include argmatch.h.
(usage): Document the change.
(CHECK_OPTION): New constant.
(long_options): --check now takes an optional argument, and is now
treated differently from 'c'.
(check_args, check_types): New constant arrays.
(check): New arg CHECKONLY, which suppresses diagnostic if -C.
(main): Parse the new options.
* tests/sort/Test.pm (02d, 02d, incompat5, incompat6):
New tests for -C.

1 files changed, 18 insertions, 4 deletions

diff --git a/doc/coreutils.texi b/doc/coreutils.texi
index 1abf45dbf..ff049bcf7 100644
--- a/doc/coreutils.texi
+++ b/doc/coreutils.texi
@@ -3342,12 +3342,26 @@ mode:
 
 @item -c
 @itemx --check
+@itemx --check=diagnose-first
 @opindex -c
 @opindex --check
 @cindex checking for sortedness
-Check whether the given files are already sorted: if they are not all
-sorted, print an error message and exit with a status of 1.
+Check whether the given file is already sorted: if it is not all
+sorted, print a diagnostic containing the first out-of-order line and
+exit with a status of 1.
 Otherwise, exit successfully.
+At most one input file can be given.
+
+@item -C
+@itemx --check=quiet
+@itemx --check=silent
+@opindex -c
+@opindex --check
+@cindex checking for sortedness
+Exit successfully if the given file is already sorted, and
+exit with status 1 otherwise.
+At most one input file can be given.
+This is like @option{-c}, except it does not print a diagnostic.
 
 @item -m
 @itemx --merge
@@ -3401,7 +3415,7 @@ Exit status:
 
 @display
 0 if no error occurred
-1 if invoked with @option{-c} and the input is not properly sorted
+1 if invoked with @option{-c} or @option{-C} and the input is not sorted
 2 if an error occurred
 @end display
 
@@ -3716,7 +3730,7 @@ disks and controllers.
 @cindex uniquifying output
 
 Normally, output only the first of a sequence of lines that compare
-equal.  For the @option{--check} (@option{-c}) option,
+equal.  For the @option{--check} (@option{-c} or @option{-C}) option,
 check that no pair of consecutive lines compares equal.
 
 This option also disables the default last-resort comparison.