dbmerge2 - Man Page
merge exactly two inputs in sorted order based on the the specified columns
Synopsis
dbmerge2 --input A.fsdb --input B.fsdb [-T TemporaryDirectory] [-nNrR] column [column...]
or
cat A.fsdb | dbmerge2 --input B.fsdb [-T TemporaryDirectory] [-nNrR] column [column...]
Description
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.
Warning: we do not verify that each input is actually sorted. Incorrect merge results will occur if they are not.
Options
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:
- -d
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.- --header H
Use H as the full Fsdb header, rather than reading a header from then input.
- --help
Show help.
- --man
Show full manual.
Sample Usage
Input
File a.fsdb:
#fsdb cid cname 11 numanal 10 pascal
File b.fsdb:
#fsdb cid cname 12 os 13 statistics
Command
dbmerge2 --input a.fsdb --input b.fsdb cname
or
cat a.fsdb | dbmerge2 --input b.fsdb cname
Output
#fsdb cid cname 11 numanal 12 os 10 pascal 13 statistics # | dbmerge2 --input a.fsdb --input b.fsdb cname
See Also
dbmerge(1), dbsort(1), Fsdb(3)
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.