Stefano Lattarini wrote: > Hi Jim. > > On 01/05/2012 04:46 PM, Jim Meyering wrote: >> 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 <meyer...@redhat.com> >> 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 <meyer...@redhat.com> >> >> + 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 >> > Wouldn't it be simpler and better to leave that redirection out altogether? > The output of the test scripts should be redirected to `.log' files by the > testsuite harness, so by being more verbose we can make those files more > informative, all without cluttering the make output.
It depends. In many cases, I would agree with you, but probably not here. I think it comes down to balancing the small repetitive cost of an added diagnostic in every log on systems lacking diff -u support vs. the probability that the clutter will ever be useful.
