ABCD
EFGH
GHIJ

##</code><code>##

ABCD\n
EFGH\n
GHIJ\n

##</code><code>##

my @array;
while ( my $line = <STDIN> ) {
    chomp $line;
    push @array, $line;
}
#.... later on...
foreach ( @array ) {
    print "$_\t";
}

##</code><code>##

{
    local $, = "\t";
    print @array, "\n";
}