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Full Discussion: UNIX loop question
Top Forums UNIX for Dummies Questions & Answers UNIX loop question Post 302930793 by bakunin on Wednesday 7th of January 2015 11:29:07 AM
Old 01-07-2015
Quote:
Originally Posted by forevertl
But now I want to run first 20 commands first using file1.txt-file20.txt in parallel, then when they are completed, run the next 20 commands in parallel, then the next 20 commands ... and so on.
I sense a slight ambiguity here and i want to clarify it before anything else:

do you want to wait for the completion of all the 20 commands before you start the next batch of twenty or do you want to start a new one any time one finishes so that always 20 jobs are running in parallel? Both is possible, but done differently.

Btw., the construction with "for" and "seq" is prone to problems and quite depcrecated, as modern shells all have to possibility to do integer math themselves. The following should work in any modern shell and do the same as your for-loop, just more robustly:

Code:
typeset -i snplist=1

while [ $snplist -le 100 ] ; do
     <your command(s) here>
     (( snplist = snplist + 1 ))
done

This User Gave Thanks to bakunin For This Post:
forevertl
 

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LEARN ABOUT DEBIAN

parallel-scp

PARALLEL-SCP(1) 														   PARALLEL-SCP(1)

NAME

       parallel-scp - parallel versions of scp

SYNOPSIS

       parallel-scp [OPTIONS] -h hosts.txt local remote

DESCRIPTION

       pssh provides a number of commands for executing against a group of computers, using SSH. It's most useful for operating on clusters of
       homogenously-configured hosts.

       parallel-scp copy files in parallel to a set of machines.

OPTIONS

       -r --recursive
	   recusively copy directories (OPTIONAL)

       -h --hosts
	   hosts file (each line "host[:port] [user]")

       -l --user
	   username (OPTIONAL)

       -p --par
	   max number of parallel threads (OPTIONAL)

       -o --outdir
	   output directory for stdout files (OPTIONAL)

       -e --errdir
	   output directory for stderr files (OPTIONAL)

       -t --timeout
	   timeout (secs) (-1 = no timeout) per host (OPTIONAL)

       -O --options
	   SSH options (OPTIONAL)

       -v --verbose
	   turn on warning and diagnostic messages (OPTIONAL)

EXAMPLE

       The following example runs hostname on three machines (IPs or hostnames) specified in the file ips.txt using login irb2 and saves the
       output in /tmp/foo.

	   # parallel-scp -h ips.txt -l irb2 /etc/hosts /tmp/hosts
	   Success on 128.112.152.122:22
	   Success on 18.31.0.190:22
	   Success on 128.232.103.201:22

ENVIRONMENT

       All four programs take similar sets of options. All of these options can be set using the following environment variables:

       o   PSSH_HOSTS
       o   PSSH_USER
       o   PSSH_PAR
       o   PSSH_OUTDIR
       o   PSSH_VERBOSE
       o   PSSH_OPTIONS

SEE ALSO

       parallel-ssh(1), parallel-slurp(1), parallel-nuke(1), parallel-rsync(1), ssh(1), scp(1),

AUTHOR

       Brent N. Chun <bnc@theether.org>

COPYING

       Copyright: 2003, 2004, 2005, 2006, 2007 Brent N. Chun

NOTES

	1. bnc@theether.org
	   mailto:bnc@theether.org

								    03/30/2009							   PARALLEL-SCP(1)
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