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Full Discussion: Optimizing bash loop
Top Forums Shell Programming and Scripting Optimizing bash loop Post 303018999 by SkySmart on Thursday 21st of June 2018 01:53:41 AM
Old 06-21-2018
Optimizing bash loop
now, i have to search for a pattern within a particular time frame which the user will provide in the following format:

Code:
19/Jun/2018:07:04,21/Jun/2018:21:30

it is easy to get tempted to attempt this search with a variation of the following awk command:

Code:
awk '/19\/Jun\/2018:07:04/,/21\/Jun\/2018:21:30/' datafile

but i think it can be more efficient than that. can i do this without having to call external utilities like awk?

im writing this code in /bin/sh. i intend to use this script on different unix flavors which includes but certainly isnt limited to ubuntu, redhat, fedora, debian.

here is the code im using to try to get the time from the log that is the closest to the time specified by the user:
Code:
        echo "${AllEpochTimes}" | awk -F"," -v c=1 -v t=${GoBackTimeEndin} '{a[NR]=$c}END{
                asort(a);d=a[NR]-t;d=d<0?-d:d;v = a[NR]
                for(i=NR-1;i>=1;i--){
                        m=a[i]-t;m=m<0?-m:m
                        if(m<d){
                        d=m;v=a[i]
                 }
                }
                print v
                }'

AllEpochTimes - contains all the converted time stamps of the log. as you can imagine, if the log file is huge, the content of this variable will skyrocket in size.
Last edited by SkySmart; 06-30-2018 at 03:00 PM..
 

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LEARN ABOUT REDHAT

igawk

IGAWK(1)							 Utility Commands							  IGAWK(1)

NAME

       igawk - gawk with include files

SYNOPSIS

       igawk [ all gawk options ] -f program-file [ -- ] file ...
       igawk [ all gawk options ] [ -- ] program-text file ...

DESCRIPTION

       Igawk is a simple shell script that adds the ability to have ``include files'' to gawk(1).

       AWK programs for igawk are the same as for gawk, except that, in addition, you may have lines like

	      @include getopt.awk

       in your program to include the file getopt.awk from either the current directory or one of the other directories in the search path.

OPTIONS

       See gawk(1) for a full description of the AWK language and the options that gawk supports.

EXAMPLES

       cat << EOF > test.awk
       @include getopt.awk

       BEGIN {
	    while (getopt(ARGC, ARGV, "am:q") != -1)
		 ...
       }
       EOF

       igawk -f test.awk

SEE ALSO

       gawk(1)

       Effective AWK Programming, Edition 1.0, published by the Free Software Foundation, 1995.

AUTHOR

       Arnold Robbins (arnold@skeeve.com).

Free Software Foundation					    Nov 3 1999								  IGAWK(1)
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