parcat - Man Page
cat files or fifos in parallel
Synopsis
Description
GNU parcat reads files or fifos in parallel. It writes full lines so there will be no problem with mixed-half-lines which you risk if you use:
(cat file1 & cat file2 &) | ...
It is faster than doing:
parallel -j0 --lb cat ::: file*
Arguments can be given on the command line or passed in on stdin (standard input).
Options
- -#
Arguments following this will be sent to the file descriptor #. E.g.
parcat -1 stdout1 stdout2 -2 stderr1 stderr2
will send stdout1 and stdout2 to stdout (standard output = file descriptor 1), and send stderr1 and stderr2 to stderr (standard error = file descriptor 2).
- --rm
Remove files after opening. As soon as the files are opened, unlink the files.
Examples
Simple line buffered output
traceroute will often print half a line. If run in parallel, two instances may half-lines of their output. This can be avoided by saving the output to a fifo and then using parcat to read the two fifos in parallel:
mkfifo freenetproject.org.fifo tange.dk.fifo traceroute freenetproject.org > freenetproject.org.fifo & traceroute tange.dk > tange.dk.fifo & parcat --rm *fifo
Reporting Bugs
GNU parcat is part of GNU parallel. Report bugs to <bug-parallel@gnu.org>.
Author
Copyright (C) 2016-2024 Ole Tange, http://ole.tange.dk and Free Software Foundation, Inc.
License
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/>.
Documentation license I
Permission is granted to copy, distribute and/or modify this documentation under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no Invariant Sections, with no Front-Cover Texts, and with no Back-Cover Texts. A copy of the license is included in the file LICENSES/GFDL-1.3-or-later.txt.
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Dependencies
GNU parcat uses Perl.