diff --git a/fhem/FHEM/00_CUL.pm b/fhem/FHEM/00_CUL.pm
index c48ea7a0b..64f8ebb28 100755
--- a/fhem/FHEM/00_CUL.pm
+++ b/fhem/FHEM/00_CUL.pm
@@ -634,7 +634,8 @@ CUL_XmitDlyHM($$$)
 {
   my ($hash,$fn,$now) = @_;
 
-  my (undef,$mTy,undef,$id) = unpack 'A8A2A6A6',$fn if(length($fn)>19);
+  my ($mTy,$id);
+  (undef,$mTy,undef,$id) = unpack 'A8A2A6A6',$fn if(length($fn)>19);
 
   if($id &&
      $modules{CUL_HM}{defptr}{$id} &&
diff --git a/fhem/FHEM/00_ZWDongle.pm b/fhem/FHEM/00_ZWDongle.pm
index 8a36a6ce2..501f604df 100644
--- a/fhem/FHEM/00_ZWDongle.pm
+++ b/fhem/FHEM/00_ZWDongle.pm
@@ -484,7 +484,8 @@ ZWDongle_Get($@)
   my $msg="";
   $a[0] = $a0 if(defined($a0));
   $msg = $ret if($ret);
-  my @r = map { ord($_) } split("", pack('H*', $ret)) if(defined($ret));
+  my @r;
+  @r = map { ord($_) } split("", pack('H*', $ret)) if(defined($ret));
 
   if($cmd eq "nodeList") {                     ############################
     $msg =~ s/^.{10}(.{58}).*/$1/;
diff --git a/fhem/FHEM/01_FHEMWEB.pm b/fhem/FHEM/01_FHEMWEB.pm
index 0c90a88d9..cb56f98ce 100644
--- a/fhem/FHEM/01_FHEMWEB.pm
+++ b/fhem/FHEM/01_FHEMWEB.pm
@@ -2212,7 +2212,8 @@ FW_returnFileAsStream($$$$$)
                   "Transfer-Encoding: chunked\r\n" .
                   "Content-Type: $type; charset=$FW_encoding\r\n\r\n");
 
-  my $d = Compress::Zlib::deflateInit(-WindowBits=>31) if($compr);
+  my $d;
+  $d = Compress::Zlib::deflateInit(-WindowBits=>31) if($compr);
   FW_outputChunk($FW_chash, $FW_RET, $d);
   FW_outputChunk($FW_chash, "<a name='top'></a>".
         "<a href='#end_of_file'>jump to the end</a><br><br>", $d)
@@ -2505,7 +2506,8 @@ FW_style($$)
       FW_addContent(">$filePath: $!</div");
       return;
     }
-    my $ret = FW_fC("rereadcfg") if($filePath eq $attr{global}{configfile});
+    my $ret;
+    $ret = FW_fC("rereadcfg") if($filePath eq $attr{global}{configfile});
     $ret = FW_fC("reload $fileName") if($fileName =~ m,\.pm$,);
     $ret = FW_Set("","","rereadicons") if($isImg);
     DoTrigger("global", "FILEWRITE $filePath", 1) if(!$ret); # Forum #32592
@@ -2672,7 +2674,8 @@ FW_makeImage(@)
       $data =~ s/ *$//g;
       $data =~ s/<svg/<svg class="$class" data-txt="$txt"/; #52967
       $name =~ m/(@.*)$/;
-      my $col = $1 if($1);
+      my $col;
+      $col = $1 if($1);
       if($col) {
         $col =~ s/@//;
         $col = "#$col" if($col =~ m/^([A-F0-9]{6})$/);
diff --git a/fhem/FHEM/10_ZWave.pm b/fhem/FHEM/10_ZWave.pm
index e8beb3f19..b21a04d2a 100644
--- a/fhem/FHEM/10_ZWave.pm
+++ b/fhem/FHEM/10_ZWave.pm
@@ -923,8 +923,9 @@ ZWave_execInits($$;$)
 
   my $NAME = $hash->{NAME};
   my $iodev = $hash->{IODev};
-  my $homeReading = ReadingsVal($iodev->{NAME}, "homeId", "") if($iodev);
-  my $CTRLID=hex($1) if($homeReading && $homeReading =~ m/CtrlNodeIdHex:(..)/);
+  my ($homeReading, $CTRLID);
+  $homeReading = ReadingsVal($iodev->{NAME}, "homeId", "") if($iodev);
+  $CTRLID = hex($1) if($homeReading && $homeReading =~ m/CtrlNodeIdHex:(..)/);
 
   # ZWavePlus devices with MCA need mcaAdd instead of associationAdd
   my $cls = AttrVal($NAME, "classes", "");
@@ -980,7 +981,8 @@ ZWave_neighborList($)
   no strict "refs";
   my $iohash = $hash->{IODev};
   my $fn = $modules{$iohash->{TYPE}}{ReadAnswerFn};
-  my ($err, $data) = &{$fn}($iohash, "neighborList", "^0180") if($fn);
+  my ($err, $data);
+  ($err, $data) = &{$fn}($iohash, "neighborList", "^0180") if($fn);
   use strict "refs";
 
   return $err if($err);
@@ -1131,7 +1133,8 @@ ZWave_Cmd($$@)
       $cmdFmt = sprintf($cmdFmt, @a);
     }
     $@ = undef;
-    my ($err, $ncmd) = eval($cmdFmt) if($cmdFmt !~ m/^\d/);
+    my ($err, $ncmd);
+    ($err, $ncmd) = eval($cmdFmt) if($cmdFmt !~ m/^\d/);
     return $err if($err);
     return $@ if($@);
     $cmdFmt = $ncmd if(defined($ncmd));
@@ -2908,8 +2911,9 @@ ZWave_configParseModel($;$)
     }
 
     if($line =~ m/^\s*<Item/) {
-      my $label = $1 if($line =~ m/label="([^"]*)"/i);
-      my $value = $1 if($line =~ m/value="([^"]*)"/i);
+      my ($label, $value);
+      $label = $1 if($line =~ m/label="([^"]*)"/i);
+      $value = $1 if($line =~ m/value="([^"]*)"/i);
       my ($item, $shortened) = ZWave_cleanString($label, $value, 1);
       $hash{$cmdName}{Item}{$item} = $value;
       $hash{$cmdName}{type} = "list";   # Forum #42604
diff --git a/fhem/FHEM/12_HMS.pm b/fhem/FHEM/12_HMS.pm
index 5407162d1..7066e7d27 100644
--- a/fhem/FHEM/12_HMS.pm
+++ b/fhem/FHEM/12_HMS.pm
@@ -87,7 +87,8 @@ HMS_Parse($$)
   my $cde = substr($msg, 11, 1);
 #                        012345678901234567890123456789
 #                        810e047f0214a001a81f000001000000 HMS100TFK
-  my $val = substr($msg, 24, 8) if(length($msg) == 32);
+  my $val;
+  $val = substr($msg, 24, 8) if(length($msg) == 32);
   if(!defined($val)) {
     Log3 $hash, 3, "Strange HMS message $msg";
     return "";
diff --git a/fhem/FHEM/92_FileLog.pm b/fhem/FHEM/92_FileLog.pm
index fad70035d..a42d8d8e1 100644
--- a/fhem/FHEM/92_FileLog.pm
+++ b/fhem/FHEM/92_FileLog.pm
@@ -836,7 +836,8 @@ FileLog_Get($@)
   }
   Log3 $name, 4, "$name get: Input file $inf, from:$from  to:$to";
 
-  my $ifh = new IO::File $inf if($inf);
+  my $ifh;
+  $ifh = new IO::File $inf if($inf);
   FileLog_seekTo($inf, $ifh, $hash, $from, $reformatFn) if($ifh);
 
   # Return the the plain file data, $outf is ignored
diff --git a/fhem/FHEM/96_allowed.pm b/fhem/FHEM/96_allowed.pm
index e0e03957e..89f143271 100644
--- a/fhem/FHEM/96_allowed.pm
+++ b/fhem/FHEM/96_allowed.pm
@@ -180,7 +180,8 @@ allowed_Authenticate($$$$)
     if($pwok && (!defined($authcookie) || $secret ne $authcookie)) {
       my $time = AttrVal($aName, "basicAuthExpiry", 0);
       if ( $time ) {
-        my ($user, $password) = split(":", decode_base64($secret)) if($secret);
+        my ($user, $password);
+        ($user, $password) = split(":", decode_base64($secret)) if($secret);
         $time = int($time*86400+time());
         # generate timestamp according to RFC-1130 in Expires
         my $expires = FmtDateTimeRFC1123($time);
@@ -248,7 +249,8 @@ allowed_CheckBasicAuth($$$$)
   my $aName = $me->{NAME};
 
   my $pwok = ($secret && $secret eq $basicAuth) ? 1 : 2;      # Base64
-  my ($user, $password) = split(":", decode_base64($secret)) if($secret);
+  my ($user, $password);
+  ($user, $password) = split(":", decode_base64($secret)) if($secret);
   ($user,$password) = ("","") if(!defined($user) || !defined($password));
 
   if($secret && $basicAuth =~ m/^{.*}$/) {
diff --git a/fhem/FHEM/98_JsonList2.pm b/fhem/FHEM/98_JsonList2.pm
index 54de485ea..28e5b54e3 100644
--- a/fhem/FHEM/98_JsonList2.pm
+++ b/fhem/FHEM/98_JsonList2.pm
@@ -37,7 +37,8 @@ JsonList2_dumpHash($$$$$$)
 {
   my ($arrp, $name, $h, $isReading, $showInternal, $attr) = @_;
   my $ret = "";
-  my %filter = map { $_=>1 } @$attr if(@$attr);
+  my %filter;
+  %filter = map { $_=>1 } @$attr if(@$attr);
   
   my @arr = grep { ($showInternal || $_ !~ m/^\./) &&
                    ($isReading || $_ eq "IODev" || !ref($h->{$_}) ) &&
diff --git a/fhem/FHEM/98_autocreate.pm b/fhem/FHEM/98_autocreate.pm
index f2fe38cd5..69d7889e8 100644
--- a/fhem/FHEM/98_autocreate.pm
+++ b/fhem/FHEM/98_autocreate.pm
@@ -570,7 +570,7 @@ CommandUsb($$)
   my ($cl, $n) = @_;
 
   return "Usage: usb [scan|create]" if("$n" !~ m/^(scan|create)$/);
-  my $scan = 1 if($n eq "scan");
+  my $scan = ($n eq "scan");
   my $ret = "";
   my $msg;
   my $dir = "/dev";
diff --git a/fhem/FHEM/98_telnet.pm b/fhem/FHEM/98_telnet.pm
index a7e2adf02..084bf4fda 100644
--- a/fhem/FHEM/98_telnet.pm
+++ b/fhem/FHEM/98_telnet.pm
@@ -139,8 +139,8 @@ telnet_Define($$$)
   my $port = $pport;
   $port =~ s/^IPV6://;
 
-  my $isServer = 1 if(defined($port) && $port =~ m/^\d+$/);
-  my $isClient = 1 if($port && $port =~ m/^(.+):\d+$/);
+  my $isServer = (defined($port) && $port =~ m/^\d+$/);
+  my $isClient = ($port && $port =~ m/^(.+):\d+$/);
 
   return "Usage: define <name> telnet { [IPV6:]<tcp-portnr> [global] | ".
                                       " [IPV6:]serverName:port }"
diff --git a/fhem/FHEM/FritzBoxUtils.pm b/fhem/FHEM/FritzBoxUtils.pm
index 079b012a7..6155ebcfb 100644
--- a/fhem/FHEM/FritzBoxUtils.pm
+++ b/fhem/FHEM/FritzBoxUtils.pm
@@ -37,8 +37,9 @@ FB_doCheckPW($$$)
               "getpage=../html/login_sid.xml" );
     $data = join("&", map {join("=", map {urlEncode($_)} split("=",$_,2))} @d);
     $data = GetFileFromURL(FB_host2URL($host)."cgi-bin/webcm", undef, $data, 1);
-    my $sid = $1 if($data =~ /<SID>(\w+)<\/SID>/i);
-    $sid = undef if($sid =~ m/^0*$/);
+    my $sid;
+    $sid = $1 if($data =~ /<SID>(\w+)<\/SID>/i);
+    $sid = undef if(defined($sid) && $sid =~ m/^0*$/);
     return $sid;
 
   } else {                            # FritzOS >= 5.50
@@ -49,8 +50,9 @@ FB_doCheckPW($$$)
 
     $data = GetFileFromURL($url, undef, $data, 1);
     return if(!$data);
-    my $sid = $1 if($data =~ /<SID>(\w+)<\/SID>/i);
-    return if($sid =~ m/^0*$/);
+    my $sid;
+    $sid = $1 if($data =~ /<SID>(\w+)<\/SID>/i);
+    return if(defined($sid) && $sid =~ m/^0*$/);
     return $sid;
   }
 }