diff --git a/src/common/unicode/generate-norm_test_table.pl b/src/common/unicode/generate-norm_test_table.pl
index 836d3abbd0..310d32fd29 100644
--- a/src/common/unicode/generate-norm_test_table.pl
+++ b/src/common/unicode/generate-norm_test_table.pl
@@ -18,9 +18,9 @@ my $output_file = $ARGV[1];
 my $output_base = basename($output_file);
 
 # Open the input and output files
-open my $INPUT, $input_file
+open my $INPUT, '<', $input_file
   or die "Could not open input file $input_file: $!";
-open my $OUTPUT, "> $output_file"
+open my $OUTPUT, '>', $output_file
   or die "Could not open output file $output_file: $!\n";
 
 # Print header of output file.
diff --git a/src/common/unicode/generate-unicode_norm_table.pl b/src/common/unicode/generate-unicode_norm_table.pl
index 41792afd3e..caf591bb22 100644
--- a/src/common/unicode/generate-unicode_norm_table.pl
+++ b/src/common/unicode/generate-unicode_norm_table.pl
@@ -16,7 +16,7 @@ my $FH;
 
 # Read list of codes that should be excluded from re-composition.
 my @composition_exclusion_codes = ();
-open($FH, "CompositionExclusions.txt")
+open($FH, '<', "CompositionExclusions.txt")
   or die "Could not open CompositionExclusions.txt: $!.";
 while (my $line = <$FH>)
 {
@@ -32,7 +32,7 @@ close $FH;
 # and character decomposition mapping
 my @characters     = ();
 my %character_hash = ();
-open($FH, "UnicodeData.txt") or die "Could not open UnicodeData.txt: $!.";
+open($FH, '<', "UnicodeData.txt") or die "Could not open UnicodeData.txt: $!.";
 while (my $line = <$FH>)
 {
 	# Split the line wanted and get the fields needed:
@@ -63,7 +63,7 @@ close $FH;
 my $num_characters = scalar @characters;
 
 # Start writing out the output file
-open my $OUTPUT, "> $output_file"
+open my $OUTPUT, '>', $output_file
   or die "Could not open output file $output_file: $!\n";
 
 print $OUTPUT <<HEADER;