\input texinfo
@setfilename parsort.info

@documentencoding utf-8

@settitle parsort - Sort (big files) in parallel

@node Top
@top parsort

@menu
* NAME::
* SYNOPSIS::
* DESCRIPTION::
* OPTIONS::
* EXAMPLE::
* PERFORMANCE::
* AUTHOR::
* LICENSE::
* DEPENDENCIES::
* SEE ALSO::
@end menu

@node NAME
@chapter NAME

parsort - Sort (big files) in parallel

@node SYNOPSIS
@chapter SYNOPSIS

@strong{parsort} @emph{options for sort}

@node DESCRIPTION
@chapter DESCRIPTION

@strong{parsort} uses GNU @strong{sort} to sort in parallel. It works just like
@strong{sort} but faster on inputs with more than 1 M lines, if you have a
multicore machine.

Hopefully these ideas will make it into GNU @strong{sort} in the future.

@node OPTIONS
@chapter OPTIONS

Same as @strong{sort}. Except:

@table @asis
@item @strong{--parallel=}@emph{N}
@anchor{@strong{--parallel=}@emph{N}}

Change the number of sorts run concurrently to @emph{N}. @emph{N} will be
increased to number of files if @strong{parsort} is given more than @emph{N}
files.

@end table

@node EXAMPLE
@chapter EXAMPLE

Sort files:

@verbatim
  parsort *.txt > sorted.txt
@end verbatim

Sort stdin (standard input) numerically:

@verbatim
  cat numbers | parsort -n > sorted.txt
@end verbatim

@node PERFORMANCE
@chapter PERFORMANCE

@strong{parsort} is faster on files than on stdin (standard input), because
different parts of a file can be read in parallel.

On a 48 core machine you should see a speedup of 3x over @strong{sort}.

@node AUTHOR
@chapter AUTHOR

Copyright (C) 2020-2023 Ole Tange,
http://ole.tange.dk and Free Software Foundation, Inc.

@node LICENSE
@chapter LICENSE

Copyright (C) 2012 Free Software Foundation, Inc.

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
at your option any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.

@node DEPENDENCIES
@chapter DEPENDENCIES

@strong{parsort} uses @strong{sort}, @strong{bash}, and @strong{parallel}.

@node SEE ALSO
@chapter SEE ALSO

@strong{sort}

@bye
