my $long_string = 'string' x 5;
print $long_string,$/;

substr( $long_string, 6 ) = ''; # truncate to 6 characters

#
# same thing, only using 4 arg substr
# substr( $long_string, 6, length($long_string) - 6, '' );
#

print $long_string,$/;
__END__
stringstringstringstringstring
string