$system1 = <STDIN>;   # this is manual input from the keyboard
#...
$system1 =~ s/\W.*//;  # what if input was " box1" (initial space)?
#...

##</code><code>##

( $system1 = <STDIN> ) =~ s/^\W*(\w+).*/$1/s; 

##</code><code>##

my %systems = ( box1 => 1, box2 => 2 );

my $Usage = "Usage:  $0  (" . join('|', sort keys %systems) . ")\n";

die $Usage unless ( @ARGV == 1 and $systems{$ARGV[0]} );

$system1 = lc( shift );