dbmerge2 - merge exactly two inputs in sorted order based on the the specified columns


    dbmerge2 --input A.fsdb --input B.fsdb [-T TemporaryDirectory] [-nNrR] column [column...]

 cat A.fsdb | dbmerge2 --input B.fsdb [-T TemporaryDirectory] [-nNrR] column [column...]


Merge exactly two sorted input files, producing one sorted result. Inputs can both be specified with "--input", or one can come from standard input and the other from "--input".

Inputs must have identical schemas (columns, column order, and field separators).

Dbmerge2 consumes a fixed amount of memory regardless of input size.

Although described above as a command line too, the command line version of dbmerge2 is not installed by default. Dbmerge2 is used primarily internal to perl; dbmerge(1) is the command-line tool for user use.


General option:
--saveoutput $OUT_REF
Save output writer (for integration with other fsdb filters).
<-T TmpDir>
where to put tmp files. Also uses environment variable TMPDIR, if -T is not specified. Default is /tmp.

Sort specification options (can be interspersed with column names):

-r or --descending
sort in reverse order (high to low)
-R or --ascending
sort in normal order (low to high)
-n or --numeric
sort numerically
-N or --lexical
sort lexicographically

This module also supports the standard fsdb options:

Enable debugging output.
-i or --input InputSource
Read from InputSource, typically a file name, or "-" for standard input, or (if in Perl) a IO::Handle, Fsdb::IO or Fsdb::BoundedQueue objects.
-o or --output OutputDestination
Write to OutputDestination, typically a file name, or "-" for standard output, or (if in Perl) a IO::Handle, Fsdb::IO or Fsdb::BoundedQueue objects.
--autorun or --noautorun
By default, programs process automatically, but Fsdb::Filter objects in Perl do not run until you invoke the run() method. The "--(no)autorun" option controls that behavior within Perl.
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File a.fsdb:

    #fsdb cid cname
    11 numanal
    10 pascal

File b.fsdb:

    #fsdb cid cname
    12 os
    13 statistics


    dbmerge2 --input a.fsdb --input b.fsdb cname


    cat a.fsdb | dbmerge2 --input b.fsdb cname


    #fsdb      cid     cname
    11 numanal
    12 os
    10 pascal
    13 statistics
    #  | dbmerge2 --input a.fsdb --input b.fsdb cname


dbmerge(1), dbsort(1), Fsdb(3)


Copyright (C) 1991-2015 by John Heidemann <johnh [at]>

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