#!/usr/bin/perl

$TIOCGWINSZ = 0x40087468;  # should be require sys/ioctl.pl

if (ioctl(STDERR, $TIOCGWINSZ, $winsize)) {
    $cols = (unpack('S4', $winsize))[1];
} else {
    $cols = 80;
}

$ARGV[0] =~ /^-(\d+)$/ && (shift, $cols = $1);
$cols--;

while (<>) {
    chop;
    $_ = substr($_,0,$cols) . "\n";
    print;
}