bug#5991: [bug#5958 PATCH] docs: document translation of obsolete sort syntax

[Eric Blake]

* doc/coreutils.texi (sort invocation): Mention the conversion.
---

How about this followup, copying the comment from Pádraig's patch into
our documentation?

 doc/coreutils.texi |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/doc/coreutils.texi b/doc/coreutils.texi
index 7561f2a..ed620f3 100644
--- a/doc/coreutils.texi
+++ b/doc/coreutils.texi
@@ -4126,6 +4126,11 @@ sort invocation
 @vindex POSIXLY_CORRECT
 On older systems, @command{sort} supports an obsolete origin-zero
 syntax @address@hidden address@hidden for specifying sort keys.
+The sequence @samp{sort address@hidden@var{x} address@hidden@var{y}}
+translates to @samp{sort address@hidden@var{x+1},@var{b}} if @var{y}
+is @samp{0} or absent, otherwise it translates to @samp{sort
address@hidden@var{x+1},@address@hidden
+
 This obsolete behavior can be enabled or disabled with the
 @env{_POSIX2_VERSION} environment variable (@pxref{Standards
 conformance}); it can also be enabled when @env{POSIXLY_CORRECT} is
-- 
1.6.6.1