BEGIN { if ($] < 5.007003) { warn "$0 requires Perl v5.7.3 or later.\n"; exit; } unless (@ARGV) { warn "Usage: $0 string [string ...]\n"; exit; } } #### BEGIN { die "$0 requires Perl v5.7.3 or later.\n" if $] < 5.007003; die "Usage: $0 string [string ...]\n" unless @ARGV; }