script to combine colums from multiple files

[Ian Petersen]

On Fri, Sep 12, 2008 at 11:03 AM, Madison Kelly <linux-5ZoueyuiTZhBDgjK7y7TUQ at public.gmane.org> wrote:
> In perl, I might do something like:
>
> -=-=-=-=-=-
> my %cols=();
> my @lines=();
> open(READ, "</path/to/file.txt") or die "Can't read... $!\n";
> while (<READ>)
> {
>        chomp;
>        my @cols=split/,/;
>        # Grab the first and third column.
>        push @{$cols{a}}, $cols[0];
>        push @{$cols{b}}, $cols[2];
> }
> close READ;
>
> open(READ, "</path/to/file2.txt") or die "Can't read... $!\n";
> while (<READ>)
> {
>        chomp;
>        my @cols=split/,/;
>        # Grab the second and fourth column.
>        push @{$cols{c}}, $cols[1];
>        push @{$cols{d}}, $cols[3];
> }
> close READ;
>
> open(WRITE, "</path/to/file2.txt") or die "Can't read... $!\n";
> foreach my $line (@lines)
> {
>        # $col will be an array ref
>        print WRITE "${$cols{a}}, ${$cols{b}}, ${$cols{c}}, ${$cols{d}}\n";
> }
>
> exit 0;
> -=-=-=-=-=-
>
> Note that I've not run this so there may be errors, but hopefully it will
> get you started.

I'm not much of a Perl hacker, so I could be wrong, but I think Madi
made a copy-and-paste error in the last call to open.  I think you
want

open(WRITE, ">/path/to/file2.txt") or die "Can't write... $!\n";

The most important change being the '>', and not the error message.

Ian
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