diff --git a/attic/keynames.pl b/attic/keynames.pl
index 23216794..a917025d 100755
--- a/attic/keynames.pl
+++ b/attic/keynames.pl
@@ -1,10 +1,11 @@
-#!/usr/bin/env perl -w
+#!/usr/bin/env perl
 
 #
 # keynames.pl
 #
 # Extracts statistics about KeyName elements from the published metadata.
 #
+use warnings;
 use lib "../build";
 use Xalan;
 use Months;
diff --git a/attic/keynames_inner.pl b/attic/keynames_inner.pl
index bed6059f..3778f942 100755
--- a/attic/keynames_inner.pl
+++ b/attic/keynames_inner.pl
@@ -1,4 +1,6 @@
-#!/usr/bin/env perl -w
+#!/usr/bin/env perl
+
+use warnings;
 use POSIX qw(floor);
 use File::Temp qw(tempfile);
 use Date::Format;
diff --git a/charting/fetch.pl b/charting/fetch.pl
index 9b01e351..47d3e51e 100755
--- a/charting/fetch.pl
+++ b/charting/fetch.pl
@@ -1,8 +1,9 @@
-#!/usr/bin/env perl -w
+#!/usr/bin/env perl
 
 #
 # fetch.pl
 #
+use warnings;
 use File::stat;
 use Months;
 
diff --git a/charting/mdui.pl b/charting/mdui.pl
index b6e14bd0..fb2a6bfd 100755
--- a/charting/mdui.pl
+++ b/charting/mdui.pl
@@ -1,8 +1,9 @@
-#!/usr/bin/env perl -w
+#!/usr/bin/env perl
 
 #
 # mdui.pl
 #
+use warnings;
 use lib "../build";
 use Xalan;
 use Months;
diff --git a/charting/saml2.pl b/charting/saml2.pl
index bc69fd04..fd790429 100755
--- a/charting/saml2.pl
+++ b/charting/saml2.pl
@@ -1,10 +1,11 @@
-#!/usr/bin/env perl -w
+#!/usr/bin/env perl
 
 #
 # saml2.pl
 #
 # Extracts statistics about SAML 2 adoption from the published metadata.
 #
+use warnings;
 use lib "../build";
 use Xalan;
 use Months;
diff --git a/charting/scopes.pl b/charting/scopes.pl
index 2e38809d..3927471b 100755
--- a/charting/scopes.pl
+++ b/charting/scopes.pl
@@ -1,10 +1,11 @@
-#!/usr/bin/env perl -w
+#!/usr/bin/env perl
 
 #
 # scopes.pl
 #
 # Extracts statistics about number of scopes from the published metadata.
 #
+use warnings;
 use lib "../build";
 use Xalan;
 use Months;
diff --git a/charting/sizes.pl b/charting/sizes.pl
index 4d36b33d..004c6e3f 100755
--- a/charting/sizes.pl
+++ b/charting/sizes.pl
@@ -1,8 +1,9 @@
-#!/usr/bin/env perl -w
+#!/usr/bin/env perl
 
 #
 # sizes.pl
 #
+use warnings;
 use lib "../build";
 use File::stat;
 use Xalan;
diff --git a/utilities/2016-09-16/doall.pl b/utilities/2016-09-16/doall.pl
index 7056b5d1..d2b8255b 100755
--- a/utilities/2016-09-16/doall.pl
+++ b/utilities/2016-09-16/doall.pl
@@ -1,4 +1,6 @@
-#!/usr/bin/env perl -W
+#!/usr/bin/env perl
+
+use warnings;
 
 open(F, "id-to-name.txt") || die "could not open id-to-name map";
 while (<F>) {
diff --git a/utilities/2016-09-16/patch.pl b/utilities/2016-09-16/patch.pl
index c47766c3..543e0a0c 100755
--- a/utilities/2016-09-16/patch.pl
+++ b/utilities/2016-09-16/patch.pl
@@ -1,4 +1,6 @@
-#!/usr/bin/env perl -W
+#!/usr/bin/env perl
+
+use warnings;
 
 my $orgID = shift @ARGV;
 
diff --git a/utilities/2016-10-06/patch.pl b/utilities/2016-10-06/patch.pl
index 638f5d7d..86744119 100755
--- a/utilities/2016-10-06/patch.pl
+++ b/utilities/2016-10-06/patch.pl
@@ -1,4 +1,6 @@
-#!/usr/bin/env perl -W
+#!/usr/bin/env perl
+
+use warnings;
 
 open(F, "id-to-name.txt") || die "could not open id-to-name map";
 while (<F>) {