[PATCH] init.sh: don't waste a subshell just to redirect stderr

[Jim Meyering]

Looking at Bruno's recent test-init.sh failure,
I noticed the unnecessary sub-shells here:

>From a815c2160e6d6cc27d934e669ef9486bab310db3 Mon Sep 17 00:00:00 2001
From: Jim Meyering <address@hidden>
Date: Thu, 5 Jan 2012 16:45:50 +0100
Subject: [PATCH] init.sh: don't waste a subshell just to redirect stderr

* tests/init.sh: In testing for diff -u and diff -c, use a
stderr-redirecting exec inside `...` rather than a subshell.
---
 ChangeLog     |    4 ++++
 tests/init.sh |    4 ++--
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index eb4a3a1..3eb41be 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,9 @@
 2012-01-05  Jim Meyering  <address@hidden>

+       init.sh: don't waste a subshell just to redirect stderr
+       * tests/init.sh: In testing for diff -u and diff -c, use a
+       stderr-redirecting exec inside `...` rather than a subshell.
+
        test-init.sh: avoid failure on HP-UX 11.00
        * tests/test-init.sh: Skip "diff -u"-comparing step when compare
        resolves to diff -c or cmp.  Reported by Bruno Haible.
diff --git a/tests/init.sh b/tests/init.sh
index 9485492..65458c7 100644
--- a/tests/init.sh
+++ b/tests/init.sh
@@ -255,7 +255,7 @@ compare_dev_null_ ()
   return 2
 }

-if diff_out_=`( diff -u "$0" "$0" < /dev/null ) 2>/dev/null`; then
+if diff_out_=`exec 2>/dev/null; diff -u "$0" "$0" < /dev/null`; then
   if test -z "$diff_out_"; then
     compare_ () { diff -u "$@"; }
   else
@@ -273,7 +273,7 @@ if diff_out_=`( diff -u "$0" "$0" < /dev/null ) 
2>/dev/null`; then
       fi
     }
   fi
-elif diff_out_=`( diff -c "$0" "$0" < /dev/null ) 2>/dev/null`; then
+elif diff_out_=`exec 2>/dev/null; diff -c "$0" "$0" < /dev/null`; then
   if test -z "$diff_out_"; then
     compare_ () { diff -c "$@"; }
   else
--
1.7.8.2.334.gd4e886