diff --git a/modules/backlinkage.pl b/modules/backlinkage.pl
index b18da5ab..202e9e1b 100644
--- a/modules/backlinkage.pl
+++ b/modules/backlinkage.pl
@@ -100,7 +100,7 @@ sub GetBackLink {
 
     our ($BacklinkBanned);
     $BacklinkBanned = "HomePage|ScratchPad" if !$BacklinkBanned;
-    tie my %backhash, 'MLDBM', $backfile, O_CREAT|O_RDWR, 0644 or die "Cannot open file $backfile $!\n";
+    tie my %backhash, 'MLDBM', $backfile, O_CREAT|O_RDWR, oct(644) or die "Cannot open file $backfile $!\n";
 
     # Search database for matches
     while ( my ($source, $hashes) = each %backhash ) {
diff --git a/modules/clustermap.pl b/modules/clustermap.pl
index 1f8956cf..af4fcf3c 100644
--- a/modules/clustermap.pl
+++ b/modules/clustermap.pl
@@ -183,14 +183,13 @@ sub CreateClusterMap {
 
 sub ClusterMapPrintRcHtml {
 	my ( @options ) = @_;
-	my $page = "";
 	my $cluster = GetParam('rcclusteronly');
 
 	if ($cluster ne "") {
 		CreateClusterMap();
 		print "Pages in this cluster:";
 		print "<ul>";
-		foreach $page (sort keys %{$ClusterMap{$cluster}}) {
+		foreach my $page (sort keys %{$ClusterMap{$cluster}}) {
 			my $title = $page;
 			$title =~ s/_/ /g;
 			print "<li>" . ScriptLink($page, $title, 'local') . "</li>";
diff --git a/modules/creole.pl b/modules/creole.pl
index 6e7259fd..14ea8be7 100644
--- a/modules/creole.pl
+++ b/modules/creole.pl
@@ -16,7 +16,7 @@ directory for your Oddmuse Wiki.
 =cut
 AddModuleDescription('creole.pl', 'Creole Markup Extension');
 
-our ($q, $bol, %InterSite, $FreeLinkPattern, $FullUrlPattern, $FreeLinkPattern, $FreeInterLinkPattern, $InterSitePattern, @MyRules, %RuleOrder, @MyInitVariables, @HtmlStack, @HtmlAttrStack);
+our ($q, $bol, %InterSite, $FullUrlPattern, $FreeLinkPattern, $FreeInterLinkPattern, $InterSitePattern, @MyRules, %RuleOrder, @MyInitVariables, @HtmlStack, @HtmlAttrStack);
 
 # ....................{ CONFIGURATION                      }....................
 
diff --git a/modules/footnotes.pl b/modules/footnotes.pl
index 72ca19c5..5f2dc0d5 100644
--- a/modules/footnotes.pl
+++ b/modules/footnotes.pl
@@ -245,7 +245,7 @@ sub FootnotesRule {
     my $is_adjacent_footnote = defined $3;
 
     # A number range (e.g., "2-5") of references to other footnotes.
-    if ($footnote_text =~ m/^(\d+)-(\d+)$/co) {
+    if ($footnote_text =~ m/^(\d+)-(\d+)$/o) {
       my ($footnote_number_first, $footnote_number_last) = ($1, $2);
       # '&#x2013;', below, is the HTML entity for a Unicode en-dash.
       print $q->a({-href=> '#footnotes' .$footnote_number_first,
@@ -258,7 +258,7 @@ sub FootnotesRule {
                   }, $footnote_number_last.($is_adjacent_footnote ? ', ' : ''));
     }
     # A number (e.g., "5") implying reference to another footnote.
-    elsif ($footnote_text =~ m/^(\d+)$/co) {
+    elsif ($footnote_text =~ m/^(\d+)$/o) {
       my $footnote_number = $1;
       print $q->a({-href=> '#footnotes' .$footnote_number,
                    -title=> 'Footnote #'.$footnote_number,
@@ -322,7 +322,7 @@ sub PrintFooterFootnotes {
 Prints the list of footnotes.
 
 =cut
-sub PrintFootnotes() {
+sub PrintFootnotes {
   print
      $q->start_div({-class=> 'footnotes'})
     .$q->h2(T($FootnotesHeaderText));
diff --git a/modules/git.pl b/modules/git.pl
index 7091b9a8..c9c94553 100644
--- a/modules/git.pl
+++ b/modules/git.pl
@@ -90,10 +90,10 @@ sub GitRun {
     # read the temporary file with the output
     close($fh);
     open(STDOUT, ">&", $oldout) or die "Can't dup \$oldout: $!";
-    open(F, '<', $fh) or die "Can't open temp file for reading: $!";
+    open(my $F, '<', $fh) or die "Can't open temp file for reading: $!";
     local $/ = undef; # Read complete files
-    $GitResult = <F>;
-    close(F);
+    $GitResult = <$F>;
+    close($F);
   } else {
     $exitStatus = system($GitBinary, @_);
   }
diff --git a/modules/header-and-footer-templates.pl b/modules/header-and-footer-templates.pl
index 347abbfd..9bc64633 100644
--- a/modules/header-and-footer-templates.pl
+++ b/modules/header-and-footer-templates.pl
@@ -30,7 +30,7 @@ sub HtmlTemplateLanguage {
   my $requested_language = $q->http('Accept-language');
   my @languages = split(/ *, */, $requested_language);
   my %Lang = ();
-  foreach $_ (@languages) {
+  foreach (@languages) {
     my $qual = 1;
     $qual = $1 if (/q=([0-9.]+)/);
     $Lang{$qual} = $1 if (/^([-a-z]+)/);
diff --git a/modules/honeypot.pl b/modules/honeypot.pl
index 609d7a7c..37ef7978 100644
--- a/modules/honeypot.pl
+++ b/modules/honeypot.pl
@@ -78,7 +78,7 @@ sub HoneyPotNewGetFormStart {
     $html .= $q->textfield({-name=>$HoneyPotOk, -id=>$HoneyPotOk,
 			    -default=>time,
 			    -size=>40, -maxlength=>250}) if $HoneyPotOk;
-    $html .= $q->label({-for=>$HoneyPotIdiot1}, 'Leave empty:'), ' ',
+    $html .= $q->label({-for=>$HoneyPotIdiot1}, 'Leave empty:') . ' ' .
       $q->textfield({-name=>$HoneyPotIdiot1, -id=>$HoneyPotIdiot1,
 		     -size=>40, -maxlength=>250}) if $HoneyPotIdiot1;
     $html .= $q->textarea(-name=>$HoneyPotIdiot2, -id=>$HoneyPotIdiot2,
diff --git a/modules/html-template.pl b/modules/html-template.pl
index 57ce9826..5ef555bb 100644
--- a/modules/html-template.pl
+++ b/modules/html-template.pl
@@ -99,7 +99,7 @@ sub HtmlTemplateLanguage {
   my $requested_language = $q->http('Accept-language');
   my @languages = split(/ *, */, $requested_language);
   my %Lang = ();
-  foreach $_ (@languages) {
+  foreach (@languages) {
     my $qual = 1;
     $qual = $1 if (/q=([0-9.]+)/);
     $Lang{$qual} = $1 if (/^([-a-z]+)/);
diff --git a/modules/load-lang.pl b/modules/load-lang.pl
index c1b34c46..aac5dc4a 100644
--- a/modules/load-lang.pl
+++ b/modules/load-lang.pl
@@ -49,7 +49,7 @@ sub LoadLanguage {
   my $requested_language = $q->http('Accept-language');
   my @languages = split(/ *, */, $requested_language);
   my %Lang = ();
-  foreach $_ (@languages) {
+  foreach (@languages) {
     my $qual = 1;
     $qual = $1 if (/q=([0-9.]+)/);
     $Lang{$qual} = $1 if (/^([-a-z]+)/);
@@ -62,7 +62,7 @@ sub LoadLanguage {
   #                . "Result: "
   #                . join(', ', map { "$_ ($Lang{$_})" } @prefs))
   #      . $q->end_html) && exit if GetParam('debug', '');
-  foreach $_ (@prefs) {
+  foreach (@prefs) {
     last if $Lang{$_} eq 'en'; # the default
     my $file = $library{$Lang{$_}};
     $file = "$LoadLanguageDir/$file" if defined $LoadLanguageDir;
diff --git a/modules/localnames.pl b/modules/localnames.pl
index 6cdf46d1..c2a6e783 100644
--- a/modules/localnames.pl
+++ b/modules/localnames.pl
@@ -313,7 +313,7 @@ sub LocalNamesNewSave {
 	   length(@collection > 1)
 	   ? join(', and ',
 		  join(', ', @collection[0 .. $#collection-1]),
-		  @collection[-1])
+		  $collection[-1])
 	   : @collection), 1)
     unless $localnames eq $Page{text};
 }
diff --git a/modules/login.pl b/modules/login.pl
index 530d1f10..867afcc1 100644
--- a/modules/login.pl
+++ b/modules/login.pl
@@ -21,7 +21,7 @@ use strict;
 AddModuleDescription('login.pl', 'Login Module');
 
 our ($q, %Action, $SiteName, @MyAdminCode, $IndexFile, $DataDir, $FullUrl);
-our ($RegistrationForm, $MinimumPasswordLength, $RegistrationsMustBeApproved, $LoginForm, $PasswordFile, $PasswordFileToUse, $PendingPasswordFile, $RequireLoginToEdit, $ConfirmEmailAddress, $UncomfirmedPasswordFile, $EmailSenderAddress, $EmailCommand, $EmailRegExp, $NotifyPendingRegistrations, $EmailConfirmationMessage, $ResetPasswordMessage, $RegistrationForm, $LogoutForm, $ResetForm, $ChangePassForm, $RequireCamelUserName, $UsernameRegExp);
+our ($RegistrationForm, $MinimumPasswordLength, $RegistrationsMustBeApproved, $LoginForm, $PasswordFile, $PasswordFileToUse, $PendingPasswordFile, $RequireLoginToEdit, $ConfirmEmailAddress, $UncomfirmedPasswordFile, $EmailSenderAddress, $EmailCommand, $EmailRegExp, $NotifyPendingRegistrations, $EmailConfirmationMessage, $ResetPasswordMessage, $LogoutForm, $ResetForm, $ChangePassForm, $RequireCamelUserName, $UsernameRegExp);
 
 my $EncryptedPassword = "";
 
@@ -372,7 +372,6 @@ sub AddUser {
 
 	my %passwords = ();
 	my %emails = ();
-	my $key;
 
 	if (open (PASSWD, $FileToUse)) {
 		while ( <PASSWD> ) {
@@ -388,7 +387,7 @@ sub AddUser {
 	$emails{$username} = $email;
 
 	open (PASSWD, ">$FileToUse");
-	foreach $key ( sort keys(%passwords)) {
+	foreach my $key ( sort keys(%passwords)) {
 		print PASSWD "$key:$passwords{$key}:$emails{$key}\n";
 	}
 	close PASSWD;
@@ -515,7 +514,6 @@ sub RemoveUser {
 
 	my %passwords = ();
 	my %emails = ();
-	my $key;
 
 	if (open (PASSWD, $FileToUse)) {
 		while ( <PASSWD> ) {
@@ -529,7 +527,7 @@ sub RemoveUser {
 	close PASSWD;
 
 	open (PASSWD, ">$FileToUse");
-	foreach $key ( sort keys(%passwords)) {
+	foreach my $key ( sort keys(%passwords)) {
 		print PASSWD "$key:$passwords{$key}:$emails{$key}\n";
 	}
 	close PASSWD;
@@ -600,7 +598,6 @@ sub ChangePassword {
 
 	my %passwords = ();
 	my %emails = ();
-	my $key;
 
 	if (open (PASSWD, $PasswordFile)) {
 		while ( <PASSWD> ) {
@@ -615,7 +612,7 @@ sub ChangePassword {
 	$passwords{$user} = $hash;
 
 	open (PASSWD, ">$PasswordFile");
-	foreach $key ( sort keys(%passwords)) {
+	foreach my $key ( sort keys(%passwords)) {
 		print PASSWD "$key:$passwords{$key}:$emails{$key}\n";
 	}
 	close PASSWD;
diff --git a/modules/pingback-server.pl b/modules/pingback-server.pl
index c6b970dc..cfcbad61 100644
--- a/modules/pingback-server.pl
+++ b/modules/pingback-server.pl
@@ -123,7 +123,7 @@ sub DoPingbackServer {
   if ($res->is_success) {
     $out =  $res->content;
   } else {
-    $out = $res->status_line, "\n";
+    $out = $res->status_line . "\n";
   }
 
   result('200 OK', 0, "Oddmuse PingbackServer! $id OK");
diff --git a/modules/private-wiki.pl b/modules/private-wiki.pl
index 608e7534..9f57d076 100644
--- a/modules/private-wiki.pl
+++ b/modules/private-wiki.pl
@@ -63,10 +63,10 @@ sub NewPrivateWikiReadFile {
   PrivateWikiInit();
   my $file = shift;
   utf8::encode($file); # filenames are bytes!
-  if (open(IN, '<', $file)) {
+  if (open(my $IN, '<', $file)) {
     local $/ = undef; # Read complete files
-    my $data = <IN>;
-    close IN;
+    my $data = <$IN>;
+    close $IN;
     return (1, '') unless $data;
     $cipher->set_iv(substr $data, 0, 16);
     $data = $cipher->decrypt(substr $data, 16);
@@ -87,13 +87,13 @@ sub NewPrivateWikiWriteStringToFile {
   PrivateWikiInit();
   my ($file, $string) = @_;
   utf8::encode($file);
-  open(OUT, '>', $file) or ReportError(Ts('Cannot write %s', $file) . ": $!", '500 INTERNAL SERVER ERROR');
+  open(my $OUT, '>', $file) or ReportError(Ts('Cannot write %s', $file) . ": $!", '500 INTERNAL SERVER ERROR');
   utf8::encode($string);
   my $iv = $random->random_bytes(16);
   $cipher->set_iv($iv);
-  print OUT $iv;
-  print OUT $cipher->encrypt(PadTo16Bytes $string);
-  close(OUT);
+  print $OUT $iv;
+  print $OUT $cipher->encrypt(PadTo16Bytes $string);
+  close($OUT);
 }
 
 # TODO is there any better way to append data to encrypted files?
@@ -323,9 +323,9 @@ sub GetRcLines { # starttime, hash of seen pages to use as a second return value
   # check the first timestamp in the default file, maybe read old log file
 
   my $filelike = ReadFile($RcFile); # CHANGED
-  open F, '<:utf8', \$filelike or die $!; # CHANGED
+  open my $F, '<:encoding(UTF-8)', \$filelike or die $!; # CHANGED
 
-  my $line = <F>;
+  my $line = <$F>;
   my ($ts) = split(/$FS/o, $line); # the first timestamp in the regular rc file
   if (not $ts or $ts > $starttime) { # we need to read the old rc file, too
     push(@result, GetRcLinesFor($RcOldFile, $starttime, \%match, \%following));
@@ -353,9 +353,9 @@ sub GetRcLinesFor {
   my @result = ();
 
   my $filelike = ReadFile($file); # CHANGED
-  open F, '<:utf8', \$filelike or return (); # CHANGED
+  open my $F, '<:encoding(UTF-8)', \$filelike or return (); # CHANGED
 
-  while (my $line = <F>) {
+  while (my $line = <$F>) {
     chomp($line);
     my ($ts, $id, $minor, $summary, $host, $username, $revision,
 	$languages, $cluster) = split(/$FS/o, $line);
diff --git a/modules/show-comments.pl b/modules/show-comments.pl
index d7008538..09c5be38 100644
--- a/modules/show-comments.pl
+++ b/modules/show-comments.pl
@@ -32,7 +32,7 @@ sub NewPrintJournal {
   my ($num, $regexp, $mode) = @_;
   if (!$CollectingJournal) {
     $CollectingJournal = 1;
-    $regexp = "^\d\d\d\d-\d\d-\d\d" unless $regexp;
+    $regexp = '^\d\d\d\d-\d\d-\d\d' unless $regexp;
     $num = 10 unless $num;
     my @pages = (grep(/$regexp/, AllPagesList()));
     if (defined &JournalSort) {
diff --git a/modules/smarttitles.pl b/modules/smarttitles.pl
index 58063e4d..dcab7a62 100644
--- a/modules/smarttitles.pl
+++ b/modules/smarttitles.pl
@@ -111,9 +111,9 @@ extensions (namely, hibernal) to obtain the title and subtitle for pages.
 
 =cut
 sub GetSmartTitles {
-  my ($title)    = $Page{text} =~ m/(?:^|\n)\#TITLE[ \t]+(.*?)\s*\n+/c;
-  my ($subtitle) = $Page{text} =~ m/(?:^|\n)\#SUBTITLE[ \t]+(.*?)\s*\n+/c;
-  my ($interlink, $suburl) = $Page{text} =~ m/(?:^|\n)\#SUBURL(:)?[ \t]+(.*?)\s*\n+/c;
+  my ($title)    = $Page{text} =~ m/(?:^|\n)\#TITLE[ \t]+(.*?)\s*\n+/;
+  my ($subtitle) = $Page{text} =~ m/(?:^|\n)\#SUBTITLE[ \t]+(.*?)\s*\n+/;
+  my ($interlink, $suburl) = $Page{text} =~ m/(?:^|\n)\#SUBURL(:)?[ \t]+(.*?)\s*\n+/;
   return ($title, $subtitle, $suburl, $interlink ? 1 : '');
 }
 
diff --git a/modules/static-copy.pl b/modules/static-copy.pl
index 541313cc..e21dad7f 100644
--- a/modules/static-copy.pl
+++ b/modules/static-copy.pl
@@ -142,7 +142,7 @@ sub StaticWriteFile {
     binmode(F);
     StaticFile($id, $mimetype, $data);
   } elsif ($html) {
-    binmode(F, ':utf8');
+    binmode(F, ':encoding(UTF-8)');
     StaticHtml($id);
   } else {
     print "no data for ";
diff --git a/modules/sync.pl b/modules/sync.pl
index 416519e8..b8be8a34 100644
--- a/modules/sync.pl
+++ b/modules/sync.pl
@@ -41,7 +41,7 @@ sub SyncNewSave {
   SyncOldSave(@_);
   # %Page is now set, but the reply was not yet sent back to the
   # browser
-  my $id = $OpenPageName;
+  my $id = $OpenPageName; # TODO masks earlier declaration
   my $data = $Page{text};
   my $user = $Page{username};
   my $summary = $Page{summary};
diff --git a/modules/toc.pl b/modules/toc.pl
index 09ad68af..73f49021 100644
--- a/modules/toc.pl
+++ b/modules/toc.pl
@@ -207,7 +207,7 @@ sub RunMyRulesToc {
       # lookahead expression resembling (?!\s+id=".*?") to work. As such, I
       # use a simple negative character class hack. *shrug*
       while ($html =~ s~<h([1-6](\s+[^i]\w+\s+=\s+"[^"]")*)>
-        ~<h$1 id="$TocAnchorPrefix$TocHeaderNumber">~cgx) {
+        ~<h$1 id="$TocAnchorPrefix$TocHeaderNumber">~gx) {
         $TocHeaderNumber++;
       }
     }
@@ -231,7 +231,7 @@ sub NewTocApplyRules {
   {
     local *STDOUT;
     open(  STDOUT, '>', \$html) or die "Can't open memory file: $!";
-    binmode STDOUT, ":utf8";
+    binmode STDOUT, ":encoding(UTF-8)";
     ($blocks, $flags) = OldTocApplyRules(@_);
     close  STDOUT;
     utf8::decode($blocks);
diff --git a/modules/upload.pl b/modules/upload.pl
index 26ea3722..7703dbdb 100644
--- a/modules/upload.pl
+++ b/modules/upload.pl
@@ -72,18 +72,18 @@ for (my $i=0; $q->param("fileToUpload$i"); $i++) {
     squeak 'Error: Filename contains invalid characters'; # this should not happen
   }
 
-  open(LOGFILE, '>>', $logFile) or squeak "$!";
-  print LOGFILE $q->param("key") . ' ' . $ENV{REMOTE_ADDR} . ' ' . $curFilename . "\n";
-  close LOGFILE;
+  open(my $LOGFILE, '>>', $logFile) or squeak "$!";
+  print $LOGFILE $q->param("key") . ' ' . $ENV{REMOTE_ADDR} . ' ' . $curFilename . "\n";
+  close $LOGFILE;
 
   my $uploadFileHandle = $q->upload("fileToUpload$i");
 
-  open(UPLOADFILE, '>', "$uploadDir/$curFilename") or squeak "$!";
-  binmode UPLOADFILE;
+  open($UPLOADFILE, '>', "$uploadDir/$curFilename") or squeak "$!";
+  binmode $UPLOADFILE;
   while (<$uploadFileHandle>) {
-    print UPLOADFILE;
+    print $UPLOADFILE;
   }
-  close UPLOADFILE;
+  close $UPLOADFILE;
   if ($q->param("nameOnly")) {
     print "$curFilename\n";
   } else {