use strict;
use warnings;

my $dir = '/etc';

while (1) {
    print "Enter pattern> ";
    chomp( my $pattern = <STDIN> );
    ## I'm talking about this line
    last unless defined $pattern and length $pattern;
    my @matched = eval {
        grep { /$pattern/ } glob "$dir/*";
    };  
    print "Error: $@" if $@; 
    print map { "$_\n" } @matched;
}