my %hash;
while ( <FILE> )
{
    my ( $key ) = ( m/^(\w+)/ )
      or next;
    $hash{$key} = 'whatever';
}

##</code><code>##

my %hash;
while ( <FILE> )
{
    my ( $key, $value ) = split /\|/, $_, 2;
    next unless $key;
    $hash{$key} = $value;
}

##</code><code>##

/^(\w+)\|/;
$hash{$1)='blah';

##</code><code>##

if ( /^(\w+)\|/ ) { $hash{$1} = 'blah' }