foreach my $file (@files) {
    if( -f $file) {
        print "<$file> is a plain file.\n";
    }
    else {
        print "<$file> is not a plain file.\n";
    }
}

##</code><code>##

use strict;
use warnings;

my @files = qw( file1 test.pl.txt file3 4);
push @files, "file5
";

foreach my $file (@files){
	print "<$file> is ", -f $file ? '' : 'not ', "a plain file.\n";
}