setlocalversion: Use "grep -q" instead of piping output to "read dummy"

In some circumstances (eg when running a build in an emacs shell
buffer), I get a spew of messages like

    grep: writing output: Broken pipe

from setlocalversion, because the "read" subshell apparently exits as
soon as it reads one line and gives EPIPE to grep.  It's not clear to
me why this way of writing the check was used instead of just using
grep -q to suppress output, but unless there is some deep reason I
don't know, this way looks cleaner to me anyway, and gets rid of the
ugly message spew.

(I double checked at http://pubs.opengroup.org/onlinepubs/009604499/utilities/grep.html
and "grep -q" is specified in POSIX / SuS, so hopefully even people
cross-compiling the kernel on some bizarre host OS can't complain
about this change)

Signed-off-by: Roland Dreier <roland@purestorage.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>

1 files changed, 1 insertions, 2 deletions

diff --git a/scripts/setlocalversion b/scripts/setlocalversion
index 4d403844e13..bd6dca8a0ab 100755
--- a/scripts/setlocalversion
+++ b/scripts/setlocalversion
@@ -75,8 +75,7 @@ scm_version()
                 [ -w . ] && git update-index --refresh --unmerged > /dev/null
 
                 # Check for uncommitted changes
-                if git diff-index --name-only HEAD | grep -v "^scripts/package" \
-                    | read dummy; then
+                if git diff-index --name-only HEAD | grep -qv "^scripts/package"; then
                         printf '%s' -dirty
                 fi