diff -urNp old/editor/ppmfade new/editor/ppmfade

--- old/editor/ppmfade	2017-11-01 11:47:49.869611402 +0100

+++ new/editor/ppmfade	2017-11-01 11:53:25.524973342 +0100

@@ -84,7 +84,7 @@ for ($n = 0; $n < @ARGV; $n++) {

         if (-e $first_file) {

         } else {

             print "I can't find first file '$first_file'\n";

-            exit 20;

+            exit 1;

         }

     } elsif ($ARGV[$n] eq "-l") {

         $n++;

@@ -92,7 +92,7 @@ for ($n = 0; $n < @ARGV; $n++) {

         if (-e $last_file) {

         } else {

             print "I can't find last file '$last_file'\n";

-            exit 20;

+            exit 1;

         }

     } elsif ($ARGV[$n] eq "-base") {

         $n++;

@@ -113,9 +113,12 @@ for ($n = 0; $n < @ARGV; $n++) {

         $mode = $BLOCK;

     } elsif ("$ARGV[$n]" eq "-mix") {

         $mode = $MIX;

+    } elsif ($ARGV[$n] eq "-help" || $ARGV[$n] eq "--help" || $ARGV[$n] eq "-h") {

+        print "ppmfade: Use 'man ppmfade' for help.\n";

+        exit 1;

     } else {

         print "Unknown argument: $ARGV[$n]\n";

-        exit 100;

+        exit 1;

     } 

 }

 #

@@ -134,18 +137,18 @@ if ($first_file ne "undefined") {

         $width = $1; $height = $2;

     } else {

         print("Unrecognized results from pnmfile on $first_file.\n");

-        exit(50);

+        exit 1;

     }

 } elsif ($last_file ne "undefined") {

     if ((`pnmfile $last_file` =~ m{\b(\d+)\sby\s(\d+)} )) { 

         $width = $1; $height = $2;

     } else {

         print("Unrecognized results from pnmfile on $first_file.\n");

-        exit(50);

+        exit 1;

     }

 } else {

     print("ppmfade:  You must specify -f or -l (or both)\n");

-    exit(90);

+    exit 1;

 }

 print("Frames are " . $width . "W x " . $height . "H\n");