diff --git a/src/backend/utils/mb/Unicode/UCS_to_BIG5.pl b/src/backend/utils/mb/Unicode/UCS_to_BIG5.pl
index 6a1321bab84..bfd4511d724 100755
--- a/src/backend/utils/mb/Unicode/UCS_to_BIG5.pl
+++ b/src/backend/utils/mb/Unicode/UCS_to_BIG5.pl
@@ -24,8 +24,8 @@
 #		 UCS-2 code in hex
 #		 # and Unicode name (not used in this script)
 
-
-require "convutils.pm";
+use strict;
+require convutils;
 
 # Load BIG5.TXT
 my $all = &read_source("BIG5.TXT");
diff --git a/src/backend/utils/mb/Unicode/UCS_to_EUC_CN.pl b/src/backend/utils/mb/Unicode/UCS_to_EUC_CN.pl
index 8df23f8be65..6b65c11a654 100755
--- a/src/backend/utils/mb/Unicode/UCS_to_EUC_CN.pl
+++ b/src/backend/utils/mb/Unicode/UCS_to_EUC_CN.pl
@@ -13,24 +13,24 @@
 # where the "u" field is the Unicode code point in hex,
 # and the "b" field is the hex byte sequence for GB18030
 
-require "convutils.pm";
+use strict;
+require convutils;
 
 # Read the input
 
-$in_file = "gb-18030-2000.xml";
+my $in_file = "gb-18030-2000.xml";
 
-open(FILE, $in_file) || die("cannot open $in_file");
+open(my $in, '<', $in_file) || die("cannot open $in_file");
 
 my @mapping;
 
-while (<FILE>)
+while (<$in>)
 {
 	next if (!m/<a u="([0-9A-F]+)" b="([0-9A-F ]+)"/);
-	$u = $1;
-	$c = $2;
+	my ($u, $c) = ($1, $2);
 	$c =~ s/ //g;
-	$ucs  = hex($u);
-	$code = hex($c);
+	my $ucs  = hex($u);
+	my $code = hex($c);
 
 	# The GB-18030 character set, which we use as the source, contains
 	# a lot of extra characters on top of the GB2312 character set that
@@ -71,6 +71,6 @@ while (<FILE>)
 		direction => 'both'
 	}
 }
-close(FILE);
+close($in);
 
 print_tables("EUC_CN", \@mapping);
diff --git a/src/backend/utils/mb/Unicode/UCS_to_EUC_JIS_2004.pl b/src/backend/utils/mb/Unicode/UCS_to_EUC_JIS_2004.pl
index b4e140b657c..b1ad19a69d8 100755
--- a/src/backend/utils/mb/Unicode/UCS_to_EUC_JIS_2004.pl
+++ b/src/backend/utils/mb/Unicode/UCS_to_EUC_JIS_2004.pl
@@ -7,27 +7,27 @@
 # Generate UTF-8 <--> EUC_JIS_2004 code conversion tables from
 # "euc-jis-2004-std.txt" (http://x0213.org)
 
-require "convutils.pm";
+use strict;
+require convutils;
 
 # first generate UTF-8 --> EUC_JIS_2004 table
 
-$in_file = "euc-jis-2004-std.txt";
+my $in_file = "euc-jis-2004-std.txt";
 
-open(FILE, $in_file) || die("cannot open $in_file");
+open(my $in, '<', $in_file) || die("cannot open $in_file");
 
 my @all;
 
-while ($line = <FILE>)
+while (my $line = <$in>)
 {
 	if ($line =~ /^0x(.*)[ \t]*U\+(.*)\+(.*)[ \t]*#(.*)$/)
 	{
-		$c              = $1;
-		$u1             = $2;
-		$u2             = $3;
-		$rest           = "U+" . $u1 . "+" . $u2 . $4;
-		$code           = hex($c);
-		$ucs1           = hex($u1);
-		$ucs2           = hex($u2);
+		# combined characters
+		my ($c, $u1, $u2) = ($1, $2, $3);
+		my $rest = "U+" . $u1 . "+" . $u2 . $4;
+		my $code = hex($c);
+		my $ucs1 = hex($u1);
+		my $ucs2 = hex($u2);
 
 		push @all, { direction => 'both',
 					 ucs => $ucs1,
@@ -38,22 +38,16 @@ while ($line = <FILE>)
 	}
 	elsif ($line =~ /^0x(.*)[ \t]*U\+(.*)[ \t]*#(.*)$/)
 	{
-		$c    = $1;
-		$u    = $2;
-		$rest = "U+" . $u . $3;
+		# non-combined characters
+		my ($c, $u, $rest) = ($1, $2, "U+" . $2 . $3);
+		my $ucs  = hex($u);
+		my $code = hex($c);
+
+		next if ($code < 0x80 && $ucs < 0x80);
+
+		push @all, { direction => 'both', ucs => $ucs, code => $code, comment => $rest };
 	}
-	else
-	{
-		next;
-	}
-
-	$ucs  = hex($u);
-	$code = hex($c);
-
-	next if ($code < 0x80 && $ucs < 0x80);
-
-	push @all, { direction => 'both', ucs => $ucs, code => $code, comment => $rest };
 }
-close(FILE);
+close($in);
 
 print_tables("EUC_JIS_2004", \@all, 1);
diff --git a/src/backend/utils/mb/Unicode/UCS_to_EUC_JP.pl b/src/backend/utils/mb/Unicode/UCS_to_EUC_JP.pl
index 0e9dd292bff..1bfd3b850e0 100755
--- a/src/backend/utils/mb/Unicode/UCS_to_EUC_JP.pl
+++ b/src/backend/utils/mb/Unicode/UCS_to_EUC_JP.pl
@@ -12,7 +12,7 @@
 # organization's ftp site.
 
 use strict;
-require "convutils.pm";
+require convutils;
 
 # Load JIS0212.TXT
 my $jis0212 = &read_source("JIS0212.TXT");
diff --git a/src/backend/utils/mb/Unicode/UCS_to_EUC_KR.pl b/src/backend/utils/mb/Unicode/UCS_to_EUC_KR.pl
index a917d067172..dffcdc40ded 100755
--- a/src/backend/utils/mb/Unicode/UCS_to_EUC_KR.pl
+++ b/src/backend/utils/mb/Unicode/UCS_to_EUC_KR.pl
@@ -16,7 +16,8 @@
 #		 UCS-2 code in hex
 #		 # and Unicode name (not used in this script)
 
-require "convutils.pm";
+use strict;
+require convutils;
 
 # Load the source file.
 
diff --git a/src/backend/utils/mb/Unicode/UCS_to_EUC_TW.pl b/src/backend/utils/mb/Unicode/UCS_to_EUC_TW.pl
index aceef5433c2..cb81c4650d5 100755
--- a/src/backend/utils/mb/Unicode/UCS_to_EUC_TW.pl
+++ b/src/backend/utils/mb/Unicode/UCS_to_EUC_TW.pl
@@ -17,7 +17,8 @@
 #		 UCS-2 code in hex
 #		 # and Unicode name (not used in this script)
 
-require "convutils.pm";
+use strict;
+require convutils;
 
 my $mapping = &read_source("CNS11643.TXT");
 
diff --git a/src/backend/utils/mb/Unicode/UCS_to_GB18030.pl b/src/backend/utils/mb/Unicode/UCS_to_GB18030.pl
index f58361024e4..7be4b7b0abe 100755
--- a/src/backend/utils/mb/Unicode/UCS_to_GB18030.pl
+++ b/src/backend/utils/mb/Unicode/UCS_to_GB18030.pl
@@ -13,24 +13,24 @@
 # where the "u" field is the Unicode code point in hex,
 # and the "b" field is the hex byte sequence for GB18030
 
-require "convutils.pm";
+use strict;
+require convutils;
 
 # Read the input
 
-$in_file = "gb-18030-2000.xml";
+my $in_file = "gb-18030-2000.xml";
 
-open(FILE, $in_file) || die("cannot open $in_file");
+open(my $in, '<', $in_file) || die("cannot open $in_file");
 
 my @mapping;
 
-while (<FILE>)
+while (<$in>)
 {
 	next if (!m/<a u="([0-9A-F]+)" b="([0-9A-F ]+)"/);
-	$u = $1;
-	$c = $2;
+	my ($u, $c) = ($1, $2);
 	$c =~ s/ //g;
-	$ucs  = hex($u);
-	$code = hex($c);
+	my $ucs  = hex($u);
+	my $code = hex($c);
 	if ($code >= 0x80 && $ucs >= 0x0080)
 	{
 		push @mapping, {
@@ -40,6 +40,6 @@ while (<FILE>)
 		}
 	}
 }
-close(FILE);
+close($in);
 
 print_tables("GB18030", \@mapping);
diff --git a/src/backend/utils/mb/Unicode/UCS_to_JOHAB.pl b/src/backend/utils/mb/Unicode/UCS_to_JOHAB.pl
index b98f9a7bf55..b249b81096c 100755
--- a/src/backend/utils/mb/Unicode/UCS_to_JOHAB.pl
+++ b/src/backend/utils/mb/Unicode/UCS_to_JOHAB.pl
@@ -15,7 +15,8 @@
 #		 UCS-2 code in hex
 #		 # and Unicode name (not used in this script)
 
-require "convutils.pm";
+use strict;
+require convutils;
 
 # Load the source file.
 
diff --git a/src/backend/utils/mb/Unicode/UCS_to_SHIFT_JIS_2004.pl b/src/backend/utils/mb/Unicode/UCS_to_SHIFT_JIS_2004.pl
index 16a53ad1d9f..6be56b5b526 100755
--- a/src/backend/utils/mb/Unicode/UCS_to_SHIFT_JIS_2004.pl
+++ b/src/backend/utils/mb/Unicode/UCS_to_SHIFT_JIS_2004.pl
@@ -7,27 +7,27 @@
 # Generate UTF-8 <--> SHIFT_JIS_2004 code conversion tables from
 # "sjis-0213-2004-std.txt" (http://x0213.org)
 
-require "convutils.pm";
+use strict;
+require convutils;
 
 # first generate UTF-8 --> SHIFT_JIS_2004 table
 
-$in_file = "sjis-0213-2004-std.txt";
+my $in_file = "sjis-0213-2004-std.txt";
 
-open(FILE, $in_file) || die("cannot open $in_file");
+open(my $in, '<', $in_file) || die("cannot open $in_file");
 
 my @mapping;
 
-while ($line = <FILE>)
+while (my $line = <$in>)
 {
 	if ($line =~ /^0x(.*)[ \t]*U\+(.*)\+(.*)[ \t]*#(.*)$/)
 	{
-		$c              = $1;
-		$u1             = $2;
-		$u2             = $3;
-		$rest           = "U+" . $u1 . "+" . $u2 . $4;
-		$code           = hex($c);
-		$ucs1           = hex($u1);
-		$ucs2           = hex($u2);
+		# combined characters
+		my ($c, $u1, $u2) = ($1, $2, $3);
+		my $rest = "U+" . $u1 . "+" . $u2 . $4;
+		my $code = hex($c);
+		my $ucs1 = hex($u1);
+		my $ucs2 = hex($u2);
 
 		push @mapping, {
 			code => $code,
@@ -40,42 +40,37 @@ while ($line = <FILE>)
 	}
 	elsif ($line =~ /^0x(.*)[ \t]*U\+(.*)[ \t]*#(.*)$/)
 	{
-		$c    = $1;
-		$u    = $2;
-		$rest = "U+" . $u . $3;
-	}
-	else
-	{
-		next;
-	}
+		# non-combined characters
+		my ($c, $u, $rest) = ($1, $2, "U+" . $2 . $3);
+		my $ucs  = hex($u);
+		my $code = hex($c);
+		my $direction;
 
-	$ucs  = hex($u);
-	$code = hex($c);
+		if ($code < 0x80 && $ucs < 0x80)
+		{
+			next;
+		}
+		elsif ($code < 0x80)
+		{
+			$direction = 'from_unicode';
+		}
+		elsif ($ucs < 0x80)
+		{
+			$direction = 'to_unicode';
+		}
+		else
+		{
+			$direction = 'both';
+		}
 
-	if ($code < 0x80 && $ucs < 0x80)
-	{
-		next;
+		push @mapping, {
+			code => $code,
+			ucs => $ucs,
+			comment => $rest,
+			direction => $direction
+		};
 	}
-	elsif ($code < 0x80)
-	{
-		$direction = 'from_unicode';
-	}
-	elsif ($ucs < 0x80)
-	{
-		$direction = 'to_unicode';
-	}
-	else
-	{
-		$direction = 'both';
-	}
-
-	push @mapping, {
-		code => $code,
-		ucs => $ucs,
-		comment => $rest,
-		direction => $direction
-	};
 }
-close(FILE);
+close($in);
 
 print_tables("SHIFT_JIS_2004", \@mapping, 1);
diff --git a/src/backend/utils/mb/Unicode/UCS_to_SJIS.pl b/src/backend/utils/mb/Unicode/UCS_to_SJIS.pl
index c8ff712af8f..17289fc5e3e 100755
--- a/src/backend/utils/mb/Unicode/UCS_to_SJIS.pl
+++ b/src/backend/utils/mb/Unicode/UCS_to_SJIS.pl
@@ -11,7 +11,7 @@
 # ftp site.
 
 use strict;
-require "convutils.pm";
+require convutils;
 
 my $charset = read_source("CP932.TXT");
 
diff --git a/src/backend/utils/mb/Unicode/UCS_to_UHC.pl b/src/backend/utils/mb/Unicode/UCS_to_UHC.pl
index b6bf3bd8f27..667f6c177c7 100755
--- a/src/backend/utils/mb/Unicode/UCS_to_UHC.pl
+++ b/src/backend/utils/mb/Unicode/UCS_to_UHC.pl
@@ -13,24 +13,24 @@
 # where the "u" field is the Unicode code point in hex,
 # and the "b" field is the hex byte sequence for UHC
 
-require "convutils.pm";
+use strict;
+require convutils;
 
 # Read the input
 
-$in_file = "windows-949-2000.xml";
+my $in_file = "windows-949-2000.xml";
 
-open(FILE, $in_file) || die("cannot open $in_file");
+open(my $in, '<', $in_file) || die("cannot open $in_file");
 
 my @mapping;
 
-while (<FILE>)
+while (<$in>)
 {
 	next if (!m/<a u="([0-9A-F]+)" b="([0-9A-F ]+)"/);
-	$u = $1;
-	$c = $2;
+	my ($u, $c) = ($1, $2);
 	$c =~ s/ //g;
-	$ucs  = hex($u);
-	$code = hex($c);
+	my $ucs  = hex($u);
+	my $code = hex($c);
 
 	next if ($code == 0x0080 || $code == 0x00FF);
 
@@ -43,7 +43,7 @@ while (<FILE>)
 		}
 	}
 }
-close(FILE);
+close($in);
 
 # One extra character that's not in the source file.
 push @mapping, { direction => 'both', code => 0xa2e8, ucs => 0x327e, comment => 'CIRCLED HANGUL IEUNG U' };
diff --git a/src/backend/utils/mb/Unicode/UCS_to_most.pl b/src/backend/utils/mb/Unicode/UCS_to_most.pl
index a3cf436eefd..b3188f3709a 100755
--- a/src/backend/utils/mb/Unicode/UCS_to_most.pl
+++ b/src/backend/utils/mb/Unicode/UCS_to_most.pl
@@ -15,9 +15,10 @@
 #		 UCS-2 code in hex
 #		 # and Unicode name (not used in this script)
 
-require "convutils.pm";
+use strict;
+require convutils;
 
-%filename = (
+my %filename = (
 	'WIN866'     => 'CP866.TXT',
 	'WIN874'     => 'CP874.TXT',
 	'WIN1250'    => 'CP1250.TXT',
@@ -46,9 +47,10 @@ require "convutils.pm";
 	'KOI8U'      => 'KOI8-U.TXT',
 	'GBK'        => 'CP936.TXT');
 
-@charsets = keys(%filename);
-@charsets = @ARGV if scalar(@ARGV);
-foreach $charset (@charsets)
+# make maps for all encodings if not specified
+my @charsets = (scalar(@ARGV) > 0) ? @ARGV : keys(%filename);
+
+foreach my $charset (@charsets)
 {
 	my $mapping = &read_source($filename{$charset});