Running commands in parallel, with or without GNU parallel. For virtualization on Macs, see /parallels. For parallel ports, see /parallel-port.

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How to get exit code of a parallel process launched by xargs?

I'd made a script for launching parallel rsync process: #! /bin/bash LIST=$1 DEST_DIR=$2 RSYNC_OPTS=$3 #echo "rsyncing From=$SRC_DIR To=$DEST_DIR RSYNC_OPTS=$RSYNC_OPTS" echo $LIST|xargs -n1 -d, ...
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1answer
24 views

Can GNU Parallel execute more parallel processes?

Can I for example execute: parallel -j 200 < list0 Where "list" has: nice -n -20 parallel -j 100 < list2 nice -n -20 parallel -j 100 < list1 Would this be feasible/possible?
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1answer
25 views

Starting GNU Parallel in background?

Is it possible to start GNU Parallel in the background, or somehow, send it to the background? I want to do this so that I can use two commands that run parallel at the same time. And why dont I ...
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1answer
20 views

Why does parallel slow down after a while?

I'm executing 60 scripts with GNU parallel(they all have wget commands in there)but I have noticed that after a few hours execution will slow down a bit. What could be causing this? I'm executing ...
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3answers
74 views

Bash, how to let some background processes run but wait for others?

I have (yet) another wait, &, && control flow question.. Say I have a script something like this where I want to do as much work at the same time as possible: # may take some hours ...
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4answers
378 views

How to run parallel processes and combine outputs when both finished

I have a bash shell script in which I pipe some data through about 5 or 6 different programs then the final results into a tab delimited file. I then do the same again for a separate similar dataset ...
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4answers
103 views

Virtual write-only file system for storing files in archive

I have an embarrassingly parallel process that creates a huge amount of nearly (but not completely) identical files. Is there a way to archive the files "on the fly", so that the data does not consume ...
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2answers
55 views

Background execution in parallel

I have a program ./pgm taking some arguments (say -a file1 -b val), which requires 2 seconds to execute. I would like to use all the processors on my machine to run this program on all the input files ...
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3answers
116 views

How to parallelize the for loop while scp the files?

I am running my below shell script from machineA which is copying the files machineB and machineC into machineA. If the files are not there in machineB, then it should be there in machineC. The below ...
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1answer
40 views

Gnu Parallel: more than one per CPU? [closed]

If I only have two cores, does parallel only run two processes at a time? I guess I'm still confused about processes, threads, and cores....
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1answer
27 views

Is it safe to resize a partition while writing to it?

I'm working on a script for automatically setting up Amazon Linux servers. I create them with 100gb virtual disks, but the main partition is always 8gb. No problem, I call sudo resize2fs /dev/sda1 at ...
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3answers
44 views

running an executable in parallel by dividing the input directory tree

Commands like find and grep would benefit greatly if they were to run in parallel. Is there a utility or a program that takes a command as an argument and makes it run in parallel by running multiple ...
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1answer
138 views

Can I force Linux to boot its initializations parallel? [closed]

I was wondering if I could manage to initialize drivers, services etc. (all these jobs what Linux does during startup) in parallel instead of sequentially. I want to aggressively lower the boot time. ...
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2answers
95 views

How can I parallelise the upload of a directory by FTP?

I need to upload a directory with a rather complicated tree (lots of subdirectories, etc.) by FTP. I am unable to compress this directory, since I do not have any access to the destination apart from ...
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1answer
48 views

GNU Parallel slows down

I'm learning GNU parallel usage and did the following: $ for i in {1.txt,2.txt}; do time wc -l $i; done 100 1.txt real 0m0.010s user 0m0.000s sys 0m0.010s 10000012 2.txt real 0m0.069s ...
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1answer
37 views

Memory-efficient utility to return N first sorted values

I would like to implement a very popular MapReduce example using only existing programs operating in a UNIX way. The problem is to find N most frequent values in an enormous amount of data. The ...
2
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1answer
22 views

No output using parallel in tandem with ag or ack

I have a list of java reserved words, first letter capitalised. $ tail -n5 ~/reservedjava.txt Break While True False Null I'm trying to look through all my java source code to find methods that ...
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4answers
305 views

Ctrl-C with two simultaneous commands in bash

I want to run two commands simultaneously in bash on a Linux machine. Therefore in my ./execute.sh bash script I put: command 1 & command 2 echo "done" However when I want to stop the bash ...
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1answer
69 views

ERROR: cube viewer is not available!

I have installed and configured the following: cube-4.2.1 opari2-1.1.1 papi-5.2.0 scalasca-2.0 scorep-1.2.1 I am trying to run scalasca -examine, but I get the following error: ERROR: cube viewer ...
2
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4answers
59 views

Parallel pausing and resuming?

I have a pretty strange thing I'm seeing as I run 8 GPG encryption jobs with GNU parallel: The command I've run is this: find . -type f -not -iname "*.gpg" | sort |parallel --gnu -j 8 --workdir ...
7
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1answer
161 views

GNU parallel vs & (I mean background) vs xargs -P

I'm confused about the difference or advantage (if any) of running a set of tasks in a .sh script using GNU parallel E.g. Ole Tange's answer: parallel ./pngout -s0 {} R{} ::: *.png rather than say ...
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3answers
173 views

Parallelize a Bash FOR Loop

I have been trying to parallelize the following script, specifically each of the three FOR loop instances, using GNU Parallel but haven't been able to. The 4 commands contained within the FOR loop run ...
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2answers
172 views

scp does not display output when used with gnu parallel

I have a short script that uses scp to copy files to a number of remote hosts (yes, I know about rdist and rsync; they both fail to work for a few of the hosts - that's not the point here; I'm only ...
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0answers
35 views

log4cxx/logger.h or libcql/cql.hpp fatal error while doing make -j4

I am running make -j4 and I am getting below exception... userName@phx5qa01c-4e23:~/build$ make -j4 [ 1%] [ 2%] Building CXX object nda/common/loadtest/CMakeFiles/loadtester.dir/LoadTester.cc.o ...
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1answer
116 views

Is there a simple way of limiting the number of child processes that execute in parallel?

I have a bash script that kicks off multiple rsync processes in parallel. I'd like to limit the number of simultaneous child processes but not serialize the whole script. Here's a simplified version ...
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1answer
60 views

Strategies for building distributed computing system with hybrid Mac and Linux systems

I want to build a distributed computing system to run Matlab, C and other programming languages for scientific computing. Now I've several old Mac machines with Lion Mac OS installed acted as web ...
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1answer
151 views

How can I issue parallel commands to remote nodes with different arguments?

I need to execute an application in parallel on multiple Ubuntu servers while supplying different arguments for different servers. I tried to google it, but could not get to the possible solution. I ...
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10answers
612 views

How do I run the same linux command in more than one tab/shell simultaneously?

Is there any tool/command in Linux that I can use to run a command in more than one tab simultaneously? I want to run the same command: ./myprog argument1 argument2 simultaneously in more than one ...
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1answer
554 views

Rsync from multiple folders to one

Is it safe to have multiple folders Rsync simultaneously into one? Each of the source folders contains a subset of the destination folder, and everybody just syncs into a master destination folder. I ...
3
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1answer
97 views

Variable declaration in parallel sh -c …

I've been trying to process the output of find with parallel, which in turn invoked a shell (some textual substitutions were needed). I observed some strange behaviour, which I cannot really explain ...
3
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2answers
134 views

Running up to X commands in parallel

I'm running something like this: find . -maxdepth 1 -type f -note -iname "*.gpg" | sort | while read file ; do echo "Encrypting $file..." gpg --trust-model always --recipient "me@myself.com" ...
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Executing piped commands in parallel

Consider the following scenario. I have two programs A and B. Program A outputs to stdout lines of strings while program B process lines from stdin. The way to use these two programs is of course ...
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104 views

How can i run a piece of code in background?

Can I run a piece of code in background instead of using another script. [sesiv@itseelm-lx4151 ~]$ cat ./testback2 #!/bin/bash start_time=$(date +%s) for i in {1..5} do ./testscript & done wait ...
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1answer
79 views

replacement inside parallel command string

I want to download multiple files and save them to the md5 sum of its name: cat list | parallel -j4 "md5=$(wget -O - {} | tee tmpfile_{#} | md5sum | cut -d ' ' -f 1); mv tmpfile_{#} $md5" but the ...
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4answers
432 views

Using GNU Parallel With Split

I'm loading a pretty gigantic file to a postgresql database. To do this I first use split in the file to get smaller files (30Gb each) and then I load each smaller file to the database using GNU ...
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0answers
239 views

MPI mpdboot error

I have a problem with mpi in a 3-box cluster with machines named head, node1 and node2 respectively. I install a newer version on node2 and the problems arises. When I include only head and node2 in ...
5
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1answer
391 views

Running parallel bash jobs on a HPC cluster using GNU parallel

On an HPC cluster I am trying to run multiple bash scripts (permute2.sh) from 1 bash script using GNU parallel, however it doesn't complete every job. It randomly completes one job, while it is stuck ...
2
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1answer
180 views

Is there a way to run process parallelly in the loop of a bash script [duplicate]

Possible Duplicate: Parallelizing a for loop The original code might look like this: for i in *; do something.py $i; done I was wondering whether I can run these jobs parallelly in the ...
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3answers
443 views

Copy multiple files to one dir with parallel

I'm using the following script to copy multiple files into one folder: { echo $BASE1; echo $BASE2; echo $BASE3; } | parallel cp -a {} $DEST Is there any way to use only one echo $BASE with brace ...
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4answers
494 views

Creating a single output stream out of three other streams produced in parallel

I have three kinds of data that are in different formats; for each data type, there is a Python script that transforms it into a single unified format. This Python script is slow and CPU-bound (to a ...
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8answers
714 views

Spreading stdin to parallel processes

I have a task that processes a list of files on stdin. The start-up time of the program is substantial, and the amount of time each file takes varies widely. I want to spawn a substantial number of ...
2
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3answers
244 views

control number of started programs in bash

As part of my research project I'm processing huge amount of data splitted up into many files. All files in folder foo have to be processed by the script myScript involving all elements of folder ...
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3answers
1k views

shell script to read from multiple files in parallel

I need to write a script that runs parallel and looks for a string in multiple files. I tried a lot of options but they slow down the speed of my processor.
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2answers
328 views

Running jobs in parallel on Ubuntu - I/O contention differences between Perl and Java

Apologies if this is off topic - it concerns the relative efficiencies of running I/O-heavy Perl/Java scripts in parallel on a Ubuntu system. I have written two simple versions of a file copy script ...
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2answers
307 views

`mpirun -np N`: what if `N` is larger than my physical cores?

Say I have a 4-core workstation, what would Linux (Ubuntu) do if I execute mpirun -np 9 XXX Will 9 run immediately together, or they will run 4 after 4? I suppose that using 9 is not good, because ...
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2k views

Remove numbers from filenames

I've a problem modifying the files' names in my Music/ directory. I have a list of names like these: $ ls 01 American Idiot.mp3 01 Articolo 31 - Domani Smetto.mp3 01 Bohemian rapsody.mp3 01 Eye of ...
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Parallel execution of a program on multiple files

I have a small script that loops through all files of a folder and executes a (usually long lasting) command. Basically it's for file in ./folder/*; do ./bin/myProgram $file > ./done/$file ...
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Is there parallel wget? Something like fping but only for downloading?

I've found only puf (Parallel URL fetcher) but could to get it work with reading urls from file and something like puf < urls.txt does not work either. The operating system installed on the ...
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2answers
1k views

Why does (GNU?) parallel fail silently, and how do I fix it?

In a larger script to post-process some simulation data I had the following line: parallel bnzip2 -- *.bz2 Which, if I understand parallel correctly (and I may not), should run n-core threads of ...
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4answers
3k views

Four tasks in parallel… how do I do that?

I have a bunch of PNG images on a directory. I have an application called pngout that I run to compress these images. This application is called by a script I did. The problem is that this script does ...