NAME

dbsort - sort rows based on the the specified columns

SYNOPSIS

    dbsort [-M MemLimit] [-T TemporaryDirectory] [-nNrR] column [column...]

DESCRIPTION

Sort all input rows as specified by the numeric or lexical columns.

Dbsort consumes a fixed amount of memory regardless of input size. (It reverts to temporary files on disk if necessary, based on the -M and -T options.)

The sort should be stable, but this has not yet been verified.

For large inputs (those that spill to disk), dbsort will do some of the merging in parallel, if possible. The <--parallel> option can control the degree of parallelism, if desired.

OPTIONS

General option:
-M MaxMemBytes
Specify an approximate limit on memory usage (in bytes). Larger values allow faster sorting because more operations happen in-memory, provided you have enough memory.
-T TmpDir
where to put tmp files. Also uses environment variable TMPDIR, if -T is not specified. Default is /tmp.
<--parallelism> N
Allow up to N merges to happen in parallel. Default is the number of CPUs in the machine.

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:

    #fsdb cid cname
    10 pascal
    11 numanal
    12 os

Command:

    cat data.fsdb | dbsort cname

Output:

    #fsdb      cid     cname
    11 numanal
    12 os
    10 pascal
    #  | dbsort cname

SEE ALSO

dbmerge(1), dbmapreduce(1), Fsdb(3)

AUTHOR and COPYRIGHT

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