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.\" ========================================================================
.\"
.IX Title "PARSORT 1"
.TH PARSORT 1 "2024-03-31" "20240322" "parallel"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
.\" way too many mistakes in technical documents.
.if n .ad l
.nh
.SH "NAME"
parsort \- Sort (big files) in parallel
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
\&\fBparsort\fR \fIoptions for sort\fR
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
\&\fBparsort\fR uses \s-1GNU\s0 \fBsort\fR to sort in parallel. It works just like
\&\fBsort\fR but faster on inputs with more than 1 M lines, if you have a
multicore machine.
.PP
Hopefully these ideas will make it into \s-1GNU\s0 \fBsort\fR in the future.
.SH "OPTIONS"
.IX Header "OPTIONS"
Same as \fBsort\fR. Except:
.IP "\fB\-\-parallel=\fR\fIN\fR" 4
.IX Item "--parallel=N"
Change the number of sorts run concurrently to \fIN\fR. \fIN\fR will be
increased to number of files if \fBparsort\fR is given more than \fIN\fR
files.
.SH "EXAMPLE"
.IX Header "EXAMPLE"
Sort files:
.PP
.Vb 1
\&  parsort *.txt > sorted.txt
.Ve
.PP
Sort stdin (standard input) numerically:
.PP
.Vb 1
\&  cat numbers | parsort \-n > sorted.txt
.Ve
.SH "PERFORMANCE"
.IX Header "PERFORMANCE"
\&\fBparsort\fR is faster on files than on stdin (standard input), because
different parts of a file can be read in parallel.
.PP
On a 48 core machine you should see a speedup of 3x over \fBsort\fR.
.SH "AUTHOR"
.IX Header "AUTHOR"
Copyright (C) 2020\-2024 Ole Tange,
http://ole.tange.dk and Free Software Foundation, Inc.
.SH "LICENSE"
.IX Header "LICENSE"
Copyright (C) 2012 Free Software Foundation, Inc.
.PP
This program is free software; you can redistribute it and/or modify
it under the terms of the \s-1GNU\s0 General Public License as published by
the Free Software Foundation; either version 3 of the License, or
at your option any later version.
.PP
This program is distributed in the hope that it will be useful,
but \s-1WITHOUT ANY WARRANTY\s0; without even the implied warranty of
\&\s-1MERCHANTABILITY\s0 or \s-1FITNESS FOR A PARTICULAR PURPOSE.\s0  See the
\&\s-1GNU\s0 General Public License for more details.
.PP
You should have received a copy of the \s-1GNU\s0 General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.
.SH "DEPENDENCIES"
.IX Header "DEPENDENCIES"
\&\fBparsort\fR uses \fBsort\fR, \fBbash\fR, and \fBparallel\fR.
.SH "SEE ALSO"
.IX Header "SEE ALSO"
\&\fBsort\fR