sort: add --sort=... option.

* src/sort.c (SORT_OPTION): New enum.
(sort_args, sort_types): Define.
(usage, long_options, main): New option --sort.
* tests/sort/Test.pm: Test it.
* doc/coreutils.texi (sort invocation): Document --sort option.
* NEWS: Mention this.

NEWS

@@ -21,6 +21,11 @@ GNU coreutils NEWS                                    -*- outline -*-
   join now verifies that the inputs are in sorted order.  This check can
   be turned off with the --nocheck-order option.
 
+  sort accepts the new option --sort=WORD, where WORD can be one of
+  general-numeric, month, numeric or random.  These are equivalent to the
+  options --general-numeric-sort/-g, --month-sort/-M, --numeric-sort/-n
+  and --random-sort/-R, resp.
+
 ** Improvements
 
   ls --color no longer outputs unnecessary escape sequences

doc/coreutils.texi

@@ -3536,8 +3536,10 @@ The @env{LC_CTYPE} locale determines character types.
 
 @item -g
 @itemx --general-numeric-sort
+@itemx --sort=general-numeric
 @opindex -g
 @opindex --general-numeric-sort
+@opindex --sort
 @cindex general numeric sort
 @vindex LC_NUMERIC
 Sort numerically, using the standard C function @code{strtod} to convert
@@ -3580,8 +3582,10 @@ This option has no effect if the stronger @option{--dictionary-order}
 
 @item -M
 @itemx --month-sort
+@itemx --sort=month
 @opindex -M
 @opindex --month-sort
+@opindex --sort
 @cindex months, sorting by
 @vindex LC_TIME
 An initial string, consisting of any amount of blanks, followed
@@ -3594,8 +3598,10 @@ can change this.
 
 @item -n
 @itemx --numeric-sort
+@itemx --sort=numeric
 @opindex -n
 @opindex --numeric-sort
+@opindex --sort
 @cindex numeric sort
 @vindex LC_NUMERIC
 Sort numerically.  The number begins each line and consists
@@ -3623,8 +3629,10 @@ appear earlier in the output instead of later.
 
 @item -R
 @itemx --random-sort
+@itemx --sort=random
 @opindex -R
 @opindex --random-sort
+@opindex --sort
 @cindex random sort
 Sort by hashing the input keys and then sorting the hash values.
 Choose the hash function at random, ensuring that it is free of

src/sort.c

@@ -1,5 +1,5 @@
 /* sort - sort lines of text (with all kinds of options).
-   Copyright (C) 1988, 1991-2007 Free Software Foundation, Inc.
+   Copyright (C) 1988, 1991-2008 Free Software Foundation, Inc.
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -329,6 +329,9 @@ Ordering options:\n\
   -n, --numeric-sort          compare according to string numerical value\n\
   -R, --random-sort           sort by random hash of keys\n\
       --random-source=FILE    get random bytes from FILE (default /dev/urandom)\n\
+      --sort=WORD             sort according to WORD:\n\
+                                general-numeric -g, month -M, numeric -n,\n\
+                                random -R\n\
   -r, --reverse               reverse the result of comparisons\n\
 \n\
 "), stdout);
@@ -391,7 +394,8 @@ enum
 {
   CHECK_OPTION = CHAR_MAX + 1,
   COMPRESS_PROGRAM_OPTION,
-  RANDOM_SOURCE_OPTION
+  RANDOM_SOURCE_OPTION,
+  SORT_OPTION
 };
 
 static char const short_options[] = "-bcCdfgik:mMno:rRsS:t:T:uy:z";
@@ -411,6 +415,7 @@ static struct option const long_options[] =
   {"numeric-sort", no_argument, NULL, 'n'},
   {"random-sort", no_argument, NULL, 'R'},
   {"random-source", required_argument, NULL, RANDOM_SOURCE_OPTION},
+  {"sort", required_argument, NULL, SORT_OPTION},
   {"output", required_argument, NULL, 'o'},
   {"reverse", no_argument, NULL, 'r'},
   {"stable", no_argument, NULL, 's'},
@@ -434,6 +439,16 @@ static char const check_types[] =
 };
 ARGMATCH_VERIFY (check_args, check_types);
 
+static char const *const sort_args[] =
+{
+  "general-numeric", "month", "numeric", "random", NULL
+};
+static char const sort_types[] =
+{
+  'g', 'M', 'n', 'R'
+};
+ARGMATCH_VERIFY (sort_args, sort_types);
+
 /* The set of signals that are caught.  */
 static sigset_t caught_signals;
 
@@ -2902,6 +2917,9 @@ main (int argc, char **argv)
 	    files[nfiles++] = optarg;
 	  break;
 
+	case SORT_OPTION:
+	  c = XARGMATCH ("--sort", optarg, sort_args, sort_types);
+	  /* Fall through. */
 	case 'b':
 	case 'd':
 	case 'f':

tests/sort/Test.pm

@@ -274,6 +274,7 @@ my @tv = (
 ["incompat4", '-c -o /dev/null', '', '', 2],
 ["incompat5", '-C -o /dev/null', '', '', 2],
 ["incompat6", '-cC', '', '', 2],
+["incompat7", '--sort=random -n', '', '', 2],
 
 # -t '\0' is accepted, as of coreutils-5.0.91
 ['nul-tab', "-k2,2 -t '\\0'", "a\0z\01\nb\0y\02\n", "b\0y\02\na\0z\01\n", 0],
@@ -289,6 +290,9 @@ my @tv = (
 # Exercise the code that enlarges the line buffer.  See the thread here:
 # http://thread.gmane.org/gmane.comp.gnu.coreutils.bugs/11006
 ['realloc-buf', '-S1', 'a'x4000 ."\n", 'a'x4000 ."\n", 0],
+
+["sort-numeric", '--sort=numeric', ".01\n0\n", "0\n.01\n", 0],
+["sort-gennum", '--sort=general-numeric', "1e2\n2e1\n", "2e1\n1e2\n", 0],
 );
 
 sub test_vector