bugGNU Parallel - build and execute command lines from standard input in parallel - Bugs: bug #36360, --ungroup unset --tag

 
 

bug #36360: --ungroup unset --tag

Submitted by:  Hans Schou <chlor>
Submitted on:  Tue 01 May 2012 08:43:56 AM UTC  
 
Category: NoneSeverity: 3 - Normal
Item Group: NoneStatus: Wont Fix
Privacy: PublicAssigned to: Ole Tange <tange>
Open/Closed: Closed

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Sun 06 May 2012 10:58:01 AM UTC, comment #1:

--ungroup bypases all postprocessing in GNU Parallel for speed. This makes it impossible for GNU Parallel to add --tag and it also creates race conditions. Thus --ungroup is only advisable if you do not care about the output.

Compare these:

seq 4 | parallel --ungroup -j0 'sleep {};echo -n {};sleep {};echo {}'

seq 4 | parallel -j0 'sleep {};echo -n {};sleep {};echo {}'

From your purpose it is clear that you are going to use the output, thus you cannot live with half a line coming from one job and the rest of the line coming from another. Thus: You are putting yourself at risk with --ungroup.

I have updated man page to reflect this.

Ole Tange <tange>
Project AdministratorIn charge of this item.
Tue 01 May 2012 08:43:56 AM UTC, original submission:

When using --tag the argument is printed at the front of the line.

If combined with --ungroup then --tag does not work.

It is the git-version
~/work/parallel/src$ ./parallel --version
GNU parallel 20120422

Test commands:

./parallel --ungroup --tag ssh {} 'hostname ; traceroute example.org' ::: foo bar

./parallel --tag ssh {} 'hostname ; traceroute example.org' ::: foo bar

Pls test this one also:

./parallel --ungroup --tag ssh {} traceroute example.org ::: foo bar

Purpose: I am sending the out to a file and as it need to be sorted later on, it is not necessary with grouping.

Hans Schou <chlor>

 

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    Follow 3 latest changes.

    Date Changed By Updated Field Previous Value => Replaced By
    Sun 06 May 2012 10:58:01 AM UTCtangeStatusNone=>Wont Fix
      Assigned toNone=>tange
      Open/ClosedOpen=>Closed

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