foreach(@array){
      my $item = $_;
      ...

##</code><code>##

   foreach(@attchfiles) {   
       my $attchfilename = $_;   
       $attchfilename =~ tr/A-Z/a-z/;    
       rename($_, $attchfilename); 
    }

##</code><code>##

   rename($_,lc) for @attchfiles;

##</code><code>##

   for(@attchfiles){
      if ( -e lc ) {
         # do something appropriate!
      } else {
         rename $_,lc;
      }
   }