diff --git a/perl-Filter.spec b/perl-Filter.spec
index 968e617..af9932c 100644
--- a/perl-Filter.spec
+++ b/perl-Filter.spec
@@ -24,7 +24,6 @@ BuildRequires:  perl(Config)
 BuildRequires:  perl(ExtUtils::MakeMaker) >= 6.76
 BuildRequires:  perl(Getopt::Long)
 BuildRequires:  perl(strict)
-BuildRequires:  sed
 # Run-time
 BuildRequires:  perl(:VERSION) >= 5.6
 BuildRequires:  perl(Carp)
@@ -74,8 +73,7 @@ sees it.
 %setup -q -n Filter-%{version}
 # Clean examples
 find examples -type f -exec chmod -x -- {} +
-sed -i -e '1 s|.*|%(perl -MConfig -e 'print $Config{startperl}')|' \
-    examples/filtdef
+perl -i -MConfig -pe 's/^#!.*/$Config{startperl}/' examples/filtdef
 
 %build
 perl Makefile.PL INSTALLDIRS=vendor NO_PACKLIST=1 NO_PERLLOCAL=1 OPTIMIZE="$RPM_OPT_FLAGS"
@@ -87,6 +85,7 @@ find $RPM_BUILD_ROOT -type f -name '*.bs' -size 0 -delete
 %{_fixperms} $RPM_BUILD_ROOT/*
 
 %check
+unset AUTHOR_TESTING FULLPERL IS_MAINTAINER PERL_CORE RELEASE_TESTING TRAVIS
 make test
 
 %files