use warnings;
use strict;

my @lines = (
    # where '\t' is a real tab
    "one\ttwo\tthree",
    "four\tfive\tsix",
);

for my $line (@lines){
    my $str = (split /\t/, $line)[0];
    $str =~ s/.$//;
    print "$str\n";
}

__END__
on
fou