dd: new status=progress level to print stats periodically

* src/dd.c: Report the transfer progress every second when the
new status=progress level is used.  Adjust the handling and
description of the status= option so that they're treated as
mutually exclusive levels, rather than flags with implicit precedence.
* doc/coreutils.texi (dd invocation): Document the new progress
status level.  Reference the new level in the description of SIGUSR1.
* tests/dd/stats.sh: Add new test for status=progress.
* tests/dd/misc.sh: Change so status=none only takes precedence
if it's the last level specified.
* NEWS: Mention the feature.

1 files changed, 9 insertions, 1 deletions

diff --git a/tests/dd/stats.sh b/tests/dd/stats.sh
index 386752e77..24b8c496b 100755
--- a/tests/dd/stats.sh
+++ b/tests/dd/stats.sh
@@ -1,5 +1,5 @@
 #!/bin/sh
-# Check robust handling of SIG{INFO,USR1}
+# Check stats output for SIG{INFO,USR1} and status=progress
 
 # Copyright (C) 2014 Free Software Foundation, Inc.
 
@@ -54,4 +54,12 @@ for open in '' '1'; do
   grep '500000000 bytes .* copied' err || { cat err; fail=1; }
 done
 
+progress_output()
+{
+  { sleep "$1"; echo 1; } | dd bs=1 status=progress of=/dev/null 2>err
+  # Progress output should be for "byte ... copied", while final is "bytes ..."
+  grep 'byte .* copied' err
+}
+retry_delay_ progress_output 1 4 || { cat err; fail=1; }
+
 Exit $fail