parallel : how to pass options to commands

Question

For parallelizing gzip compression:

parallel gzip ::: myfile_*

does the job but how to pass gzip options such as -r or -9

I tried parallel gzip -r -9 ::: myfile_* and parallel gzip ::: 9 r myfile_*

but it doesn't work.

when I tried parallel "gzip -9 -r" ::: myfile_*

I get this error message :

gzip: compressed data not written to a terminal. Use -f to force compression

Also the -r switch for recursively adding directories is not working.

....

Similarly for other commands: how to pass the options while using parallel ?

score 2 · Accepted Answer · answered Jul 06 '13 at 17:00

2

You have the correct syntax:

parallel gzip -r -9 ::: myfile_*

So something else is wrong. What is the output of

parallel --version

You can find more about GNU Parallel at: http://www.gnu.org/s/parallel/

You can install GNU Parallel in just 10 seconds with:

wget -O - pi.dk/3 | sh

Watch the intro video on

http://www.youtube.com/playlist?list=PL284C9FF2488BC6D1

answered Jul 06 '13 at 17:00

Ole Tange

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my version is 20121222. I downloaded from fedora repositories. perhaps i should download the latest verstion – WYSIWYG Jul 07 '13 at 06:21
Version 20121222 is fine. But Fedora is known to mess up GNU Parallel for their users: http://stackoverflow.com/questions/16448887/gnu-parallel-not-working-at-all So please post the full output of 'parallel --version' - not just the version number. – Ole Tange Jul 07 '13 at 13:52
cool... so you are the developer.. well it gives the following output: `WARNING: YOU ARE USING --tollef. IF THINGS ARE ACTING WEIRD USE --gnu. GNU parallel 20121222 Copyright (C) 2007,2008,2009,2010,2011,2012 Ole Tange and Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later This is free software: you are free to change and redistribute it. GNU parallel comes with no warranty. Web site: http://www.gnu.org/software/parallel When using GNU Parallel for a publication please cite: O. Tange (2011): GNU Parallel - The Command-Line Power Too` – WYSIWYG Jul 07 '13 at 18:49
The warning should give you a hint: WARNING: YOU ARE USING --tollef. IF THINGS ARE ACTING WEIRD USE --gnu. – Ole Tange Oct 02 '13 at 13:17
And did you follow it? (i.e. either remove --tollef or add --gnu) – Ole Tange Oct 11 '13 at 09:05
My parallel doesn't work with `--version` (get error) and none of the above either (nothing happens) =( – antonavy Jul 26 '16 at 22:33
@antonavy You probably have installed a program called 'parallel' which is not GNU Parallel. Maybe an old version of 'moreutils'? https://www.gnu.org/software/parallel/history.html – Ole Tange Jul 27 '16 at 06:12

score 2 · Answer 2 · answered Jul 06 '13 at 17:04

(I don't think this question belongs here. Maybe superuser.com?)

parallel gzip -r -9 ::: * worked fine for me, going into directories and all. I am using parallel version 20130622.

Note that with this approach, each directory will be a single task. You may instead want to pipe the output of find to parallel to give each file separately to parallel.

score 2 · Answer 3 · answered Jul 18 '13 at 20:59

2

Have you tried the --gnu flag for parallel??

parallel -j+0 --gnu "command"....

In some systems (like Ubuntu) is disabled by default.

answered Jul 18 '13 at 20:59

mikyatope

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parallel : how to pass options to commands

3 Answers3