my $file = "file";
my $temp = "temp";

foreach (1..5){
open $file, '>', "$temp$_";
print $file "THIS IS DATA";
}
[download]

Whatever you may think of the use of  $_ this code doesn't compile under strictures because  $file is not undefined. Quoth the open docs (emphasis added):

If FILEHANDLE is an undefined scalar variable (or array or hash
element), a new filehandle is autovivified, meaning that the
variable is assigned a reference to a newly allocated anonymous
filehandle. Otherwise if FILEHANDLE is an expression, its value
is the real filehandle. (This is considered a symbolic
reference, so "use strict "refs"" should *not* be in effect.)

c:\@Work\Perl\monks\james28909>perl -wMstrict -e
"my $file = 'file';
 my $temp = 'temp';
 ;;
 foreach (1..5){
   open $file, '>', qq{$temp$_};
   print $file 'THIS IS DATA';
   }
"
Can't use string ("file") as a symbol ref while "strict refs" in use a
+t -e line 1.
[download]

(Talk about rearranging the deck chairs on the Titanic! :)