#!/usr/bin/perl

#
# dbcolmerge.pm
# Copyright (C) 1991-2022 by John Heidemann <johnh@isi.edu>
#
# This program is distributed under terms of the GNU general
# public license, version 2.  See the file COPYING
# in $dblibdir for details.
#


=head1 NAME

dbcolmerge - merge multiple columns into one

=head1 SYNOPSIS

dbcolmerge [-C ElementSeparator] [columns...]

=head1 DESCRIPTION

For each row, merge multiple columns down to a single column (always a string),
joining elements with ElementSeparator (defaults to a single underscore).

=head1 OPTIONS

=over 4

=item B<-C S> or B<--element-separator S>

Specify the separator used to join columns.
(Defaults to a single underscore.)

=item B<-e E> or B<--empty E>

give value E as the value for empty (null) records

=back

=for comment
begin_standard_fsdb_options

This module also supports the standard fsdb options:

=over 4

=item B<-d>

Enable debugging output.

=item B<-i> or B<--input> InputSource

Read from InputSource, typically a file name, or C<-> for standard input,
or (if in Perl) a IO::Handle, Fsdb::IO or Fsdb::BoundedQueue objects.

=item B<-o> or B<--output> OutputDestination

Write to OutputDestination, typically a file name, or C<-> for standard output,
or (if in Perl) a IO::Handle, Fsdb::IO or Fsdb::BoundedQueue objects.

=item B<--autorun> or B<--noautorun>

By default, programs process automatically,
but Fsdb::Filter objects in Perl do not run until you invoke
the run() method.
The C<--(no)autorun> option controls that behavior within Perl.

=item B<--header H>

Use H as the full Fsdb header, rather than reading a header from
then input.

=item B<--help>

Show help.

=item B<--man>

Show full manual.

=back

=for comment
end_standard_fsdb_options


=head1 SAMPLE USAGE

=head2 Input:

    #fsdb      first   last
    John    Heidemann
    Greg    Johnson
    Root    -
    # this is a simple database
    #  | /home/johnh/BIN/DB/dbcol fullname
    #  | dbcolrename fullname first_last
    #  | /home/johnh/BIN/DB/dbcolsplit -C _ first_last
    #  | /home/johnh/BIN/DB/dbcol first last

=head2 Command:

    cat data.fsdb | dbcolmerge -C _ first last

=head2 Output:

    #fsdb      first   last    first_last
    John    Heidemann       John_Heidemann
    Greg    Johnson Greg_Johnson
    Root    -        Root_
    # this is a simple database
    #  | /home/johnh/BIN/DB/dbcol fullname
    #  | dbcolrename fullname first_last
    #  | /home/johnh/BIN/DB/dbcolsplit first_last
    #  | /home/johnh/BIN/DB/dbcol first last
    #  | /home/johnh/BIN/DB/dbcolmerge -C _ first last


=head1 SEE ALSO

L<Fsdb>.
L<dbcolsplittocols>.
L<dbcolsplittorows>.
L<dbcolrename>.


=cut


# WARNING: This code is derived from dbcolmerge.pm; that is the master copy.

use Fsdb::Filter::dbcolmerge;
my $f = new Fsdb::Filter::dbcolmerge(@ARGV);
$f->setup_run_finish;  # or could just --autorun
exit 0;


=head1 AUTHOR and COPYRIGHT

Copyright (C) 1991-2022 by John Heidemann <johnh@isi.edu>

This program is distributed under terms of the GNU general
public license, version 2.  See the file COPYING
with the distribution for details.

=cut

1;