Bash script search, improve performance with large files Post: 303033044

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Top Forums Shell Programming and Scripting Bash script search, improve performance with large files Post 303033044 by SDohmen on Friday 29th of March 2019 04:53:59 AM

03-29-2019

Registered User

Quote:

Originally Posted by Peasant

When processing extremely large files you might consider using split first.
Then in multicore environments spawn several awks or greps to process it in parallel from shell script.
There are also GNU tools which offer parallelism without shell logic.

Should be a bit tougher to program, but processing time will be reduced significantly if you have cores and disks are fast to service.

Memory also comes in play, since split will read the files, and operating system will cache those files in memory, if the same is available.
Making those awks or greps processes much faster on read operations.

Of course, limit being free memory on the system and configuration of the file system caching in general.
In default configurations file system caching will be able to use a large portion free memory on most linux / unix systems i've seen.

Hope that helps
Regards
Peasant.

This sounds very interesting but there are 2 issues.

1. I have to split the files in smaller files (around 5k i guess) which isn't a big deal but a little bit annoying.
2. Since this is running in a script i have no idea how to call multiple instances of awk at the same time. Everything i know says that it handles each part of the script after each other and not at the same time. If you have an idea how to accomplish that please let me know since it does sound interesting/promising.

CPU and MEM arent the issue as they are sufficient. The only thing that can stall the script are the other scripts that are running also. I tried spreading them out as much as possible but some just take quite long to run and thats why i want to slim them down so they dont run together.

SDohmen

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bashbug

BASHBUG(1)						      General Commands Manual							BASHBUG(1)

NAME

       bashbug - report a bug in bash

SYNOPSIS

       bashbug [--version] [--help] [email-address]

DESCRIPTION

       bashbug	is  a shell script to help the user compose and mail bug reports concerning bash in a standard format.	bashbug invokes the editor
       specified by the environment variable EDITOR on a temporary copy of the bug report format outline. The user must fill  in  the  appropriate
       fields  and  exit  the  editor.	 bashbug  then	mails the completed report to bug-bash@gnu.org, or email-address.  If the report cannot be
       mailed, it is saved in the file dead.bashbug in the invoking user's home directory.

       The bug report format outline consists of several sections.  The first section provides information about the  machine,	operating  system,
       the  bash  version, and the compilation environment.  The second section should be filled in with a description of the bug.  The third sec-
       tion should be a description of how to reproduce the bug.  The optional fourth section is for a proposed fix.  Fixes are encouraged.

ENVIRONMENT

       bashbug will utilize the following environment variables if they exist:

       EDITOR Specifies the preferred editor. If EDITOR is not set, bashbug defaults to emacs.

       HOME   Directory in which the failed bug report is saved if the mail fails.

       TMPDIR Directory in which to create temporary files and directories.

SEE ALSO

       bash(1)

AUTHORS

       Brian Fox, Free Software Foundation
       bfox@gnu.org

       Chet Ramey, Case Western Reserve University
       chet@po.cwru.edu

GNU Bash-4.0							   1998 July 30 							BASHBUG(1)