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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

queuedefs

queuedefs(4)							   File Formats 						      queuedefs(4)

NAME

       queuedefs - queue description file for at, batch, and cron

SYNOPSIS

       /etc/cron.d/queuedefs

DESCRIPTION

       The queuedefs file describes the characteristics of the queues managed by cron(1M). Each non-comment line in this file describes one queue.
       The format of the lines are as follows:

	      q.[njobj][nicen][nwaitw]

       The fields in this line are:

       q	The name of the queue. a is the default queue for jobs started by at(1); b is the default queue for jobs  started  by  batch  (see
		at(1)); c is the default queue for jobs run from a crontab(1) file.

       njob	The  maximum  number of jobs that can be run simultaneously in that queue; if more than njob jobs are ready to run, only the first
		njob jobs will be run, and the others will be run as jobs that are currently running terminate.  The default value is  100.

       nice	The nice(1) value to give to all jobs in that queue that are not run with a user ID of super-user.  The default value is 2.

       nwait	The number of seconds to wait before rescheduling a job that was deferred because more than njob jobs were running in  that  job's
		queue, or because the system-wide limit of jobs executing has been reached.  The default value is 60.

       Lines beginning with # are comments, and are ignored.

EXAMPLES

       Example 1: A sample file.

       #
       #
       a.4j1n
       b.2j2n90w

       This  file  specifies that the a queue, for at jobs, can have up to 4 jobs running simultaneously; those jobs will be run with a nice value
       of 1.  As no nwait value was given, if a job cannot be run because too many other jobs are running cron will wait 60 seconds before  trying
       again to run it.

       The  b  queue, for batch(1) jobs, can have up to 2 jobs running simultaneously; those jobs will be run with a nice(1) value of 2.  If a job
       cannot be run because too many other jobs are running, cron(1M) will wait 90 seconds before trying again to run it. All	other  queues  can
       have up to 100 jobs running simultaneously; they will be run with a nice value of 2, and if a job cannot be run because too many other jobs
       are running cron will wait 60 seconds before trying again to run it.

FILES

       /etc/cron.d/queuedefs	       queue description file for  at, batch, and  cron.

SEE ALSO

       at(1), crontab(1), nice(1), cron(1M)

SunOS 5.10							    1 Mar 1994							      queuedefs(4)
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