nl: ensure '-b n' option displays file content

The command 'nl -b n' should output no line numbers, just some
spaces as a placeholder followed by the actual file content.

Add tests for line numbering by cat and nl.  The correct results
were obtained from coreutils.

function                                             old     new   delta
print_numbered_lines                                 152     157      +5
.rodata                                           182456  182453      -3
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/1 up/down: 5/-3)                Total: 2 bytes

Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/coreutils/cat.c b/coreutils/cat.c
index 65f0648f9..dae6089bd 100644
--- a/coreutils/cat.c
+++ b/coreutils/cat.c
@@ -201,7 +201,7 @@ int cat_main(int argc UNUSED_PARAM, char **argv)
                 ns.start = 1;
                 ns.inc = 1;
                 ns.sep = "\t";
-                ns.empty_str = "\n";
+                ns.empty_str = NULL;
                 ns.all = !(opts & CAT_OPT_b); /* -n without -b */
                 ns.nonempty = (opts & CAT_OPT_b); /* -b (with or without -n) */
                 exitcode = EXIT_SUCCESS;