PARCAT(1)

✨ PARCAT(1) ✨

okay bestie, welcome to the parallel manual, page one and only: parcat 💅 it's the cat files or fifos in parallel situation and honestly? it's giving main character energy for your terminal. let's get into it 🫶

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🌸 NAME 🌸

parcat — cat files or fifos in parallel ✨

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🎀 SYNOPSIS 🎀

parcat [--rm] [-#] file(s) [-#] file(s)

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🦋 DESCRIPTION 🦋

so GNU parcat reads files or fifos in parallel, no cap. and here's the slay part: it writes full lines, so you will never ever get the cursed mixed-half-lines situation that you risk if you do this:

(cat file1 & cat file2 &) | ...

and it's also faster than doing this:

parallel -j0 --lb cat ::: file*

lowkey iconic. also, arguments can be given on the command line or passed in on stdin (standard input) — your choice, bestie, both work 💖

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💅 OPTIONS 💅

• -# — arguments following this will be sent to the file descriptor #. like, for example:

parcat -1 stdout1 stdout2 -2 stderr1 stderr2

that will send stdout1 and stdout2 to stdout (standard output = file descriptor 1), and send stderr1 and stderr2 to stderr (standard error = file descriptor 2). chef's kiss routing, fr fr 🍓

• --rm — remove files after opening. as soon as the files are opened, unlink the files. poof, gone, no crumbs 🧚

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🌈 EXAMPLES 🌈

⭐ Simple line buffered output

traceroute will often print half a line. and if you run it in parallel, two instances may print half-lines of their output 😭 the way that just ruins everything. 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

ate. no half-lines, no drama 💜

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💀 REPORTING BUGS 💀

GNU parcat is part of GNU parallel. report bugs to <bug-parallel@gnu.org>. don't be shy, they wanna hear it 🙈

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👑 AUTHOR 👑

Copyright (C) 2016-2026 Ole Tange, http://ole.tange.dk and Free Software Foundation, Inc.

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💖 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/>.

okay so this part is the serious part bestie — no warranty, read it properly 🫶

🎀 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.

🦋 Documentation license II 🦋

You are free:

• to Share to copy, distribute and transmit the work
• to Remix to adapt the work

Under the following conditions:

• Attribution — You must attribute the work in the manner specified by the author or licensor (but not in any way that suggests that they endorse you or your use of the work).
• Share Alike — If you alter, transform, or build upon this work, you may distribute the resulting work only under the same, similar or a compatible license.

With the understanding that:

• Waiver — Any of the above conditions can be waived if you get permission from the copyright holder.
• Public Domain — Where the work or any of its elements is in the public domain under applicable law, that status is in no way affected by the license.
• Other Rights — In no way are any of the following rights affected by the license:
  • Your fair dealing or fair use rights, or other applicable copyright exceptions and limitations;
  • The author's moral rights;
  • Rights other persons may have either in the work itself or in how the work is used, such as publicity or privacy rights.
• Notice — For any reuse or distribution, you must make clear to others the license terms of this work.

A copy of the full license is included in the file as LICENCES/CC-BY-SA-4.0.txt

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🧚 DEPENDENCIES 🧚

GNU parcat uses Perl. 💜

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🔥 SEE ALSO 🔥

cat(1), parallel(1)

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and that's the whole page, bestie! this one came from the 20260122 source, dated 2026-01-31 — yes it's got both, she contains multitudes 💅 mwah, go cat some fifos in parallel, ily 🫶✨