* NEWS: Mention that df exits with nonzero status if it generates

no output.  This change was in 6.0 but inadvertently unmentioned.
* doc/coreutils.texi (df invocation): df exits nonzero if it outpus
nothing.
* src/df.c (file_systems_processed): Renamed from n_valid_args, and now
a boolean.
(show_dev): Don't set it until we actually output something.
Print the header if this is the first output.
(main): Don't print a header, as that is now show_dev's job.
* tests/misc/Makefile.am (TESTS): Add df.
* tests/misc/df: New file.

1 files changed, 17 insertions, 0 deletions

diff --git a/tests/misc/df b/tests/misc/df
new file mode 100755
index 000000000..b1efe61ab
--- /dev/null
+++ b/tests/misc/df
@@ -0,0 +1,17 @@
+#!/bin/sh
+# Ensure that "df ." outputs a header.
+
+if test "$VERBOSE" = yes; then
+  set -x
+  df --version
+fi
+
+case `df .` in
+*'
+'*)
+  fail=0;;
+*)
+  fail=1;;
+esac
+
+(exit $fail); exit $fail