1PARCAT(1) parallel PARCAT(1)
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6 parcat - cat files or fifos in parallel
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9 parcat [--rm] [-#] file(s) [-#] file(s)
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12 GNU parcat reads files or fifos in parallel. It writes full lines so
13 there will be no problem with mixed-half-lines which you risk if you
14 use:
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16 (cat file1 & cat file2 &) | ...
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18 It is faster than doing:
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20 parallel -j0 --lb cat ::: file*
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22 Arguments can be given on the command line or passed in on stdin
23 (standard input).
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26 -# Arguments following this will be sent to the file descriptor
27 #. E.g.
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29 parcat -1 stdout1 stdout2 -2 stderr1 stderr2
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31 will send stdout1 and stdout2 to stdout (standard output =
32 file descriptor 1), and send stderr1 and stderr2 to stderr
33 (standard error = file descriptor 2).
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35 --rm Remove files after opening. As soon as the files are opened,
36 unlink the files.
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39 Simple line buffered output
40 traceroute will often print half a line. If run in parallel, two
41 instances may half-lines of their output. This can be avoided by saving
42 the output to a fifo and then using parcat to read the two fifos in
43 parallel:
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45 mkfifo freenetproject.org.fifo tange.dk.fifo
46 traceroute freenetproject.org > freenetproject.org.fifo &
47 traceroute tange.dk > tange.dk.fifo &
48 parcat --rm *fifo
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51 GNU parcat is part of GNU parallel. Report bugs to
52 <bug-parallel@gnu.org>.
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55 Copyright (C) 2016-2022 Ole Tange, http://ole.tange.dk and Free
56 Software Foundation, Inc.
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59 This program is free software; you can redistribute it and/or modify it
60 under the terms of the GNU General Public License as published by the
61 Free Software Foundation; either version 3 of the License, or at your
62 option any later version.
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64 This program is distributed in the hope that it will be useful, but
65 WITHOUT ANY WARRANTY; without even the implied warranty of
66 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
67 General Public License for more details.
68
69 You should have received a copy of the GNU General Public License along
70 with this program. If not, see <http://www.gnu.org/licenses/>.
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72 Documentation license I
73 Permission is granted to copy, distribute and/or modify this
74 documentation under the terms of the GNU Free Documentation License,
75 Version 1.3 or any later version published by the Free Software
76 Foundation; with no Invariant Sections, with no Front-Cover Texts, and
77 with no Back-Cover Texts. A copy of the license is included in the
78 file LICENSES/GFDL-1.3-or-later.txt.
79
80 Documentation license II
81 You are free:
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83 to Share to copy, distribute and transmit the work
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85 to Remix to adapt the work
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87 Under the following conditions:
88
89 Attribution
90 You must attribute the work in the manner specified by the
91 author or licensor (but not in any way that suggests that they
92 endorse you or your use of the work).
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94 Share Alike
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96 distribute the resulting work only under the same, similar or
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99 With the understanding that:
100
101 Waiver Any of the above conditions can be waived if you get
102 permission from the copyright holder.
103
104 Public Domain
105 Where the work or any of its elements is in the public domain
106 under applicable law, that status is in no way affected by the
107 license.
108
109 Other Rights
110 In no way are any of the following rights affected by the
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113 • Your fair dealing or fair use rights, or other
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122 Notice For any reuse or distribution, you must make clear to others
123 the license terms of this work.
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125 A copy of the full license is included in the file as
126 LICENCES/CC-BY-SA-4.0.txt
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129 GNU parcat uses Perl.
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132 cat(1), parallel(1)
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13620211222 2021-12-25 PARCAT(1)