doc: warn about tabs command (bug#57946)

diff --git a/doc/coreutils.texi b/doc/coreutils.texi
index e6eae44dc79eb04ff387b81ce022e6030937d541..adf957e612e2d9732b55a9f73a7e983c6f9e590a 100644 (file)
--- a/doc/coreutils.texi
+++ b/doc/coreutils.texi
@@ -8295,6 +8295,15 @@ TAB following a non-ASCII byte.  You can avoid that issue by using the
 @option{-T0} option or put @code{TABSIZE=0} in your environment, to tell
 @command{ls} to align using spaces, not tabs.
 
+If set a terminal's hardware tabs to anything other than the default,
+you should also use a @command{--tabsize} option or @env{TABSIZE}
+environment variable either to match the hardware tabs, or to disable
+the use of hardware tabs.  Otherwise, the output of @command{ls} may
+not line up.  For example, if you run the shell command @samp{tabs -4}
+to set hardware tabs to every four columns, you should also run
+@samp{export TABSIZE=4} or @samp{export TABSIZE=0}, or use the
+corresponding @option{--tabsize} options.
+
 @item -w @var{cols}
 @itemx --width=@var{cols}
 @opindex -w