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Full Discussion: understanding awk in this script
Top Forums UNIX for Advanced & Expert Users understanding awk in this script Post 302453570 by coolrock on Wednesday 15th of September 2010 06:53:05 PM
Old 09-15-2010
understanding awk in this script
i am analyzing a query written by another developer ,need to understand part of script
am looking at a code ..and it converts comma files to pipe delimited and also takes away quotes from any columns,
source field format: 2510,"Debbie",NewYork
changes to
target: 2510|Debbie|NewYork

*************Script********
Line 1 cat $out_location/BACI_1000|\
Line 2 awk -v sep=' "" ' \ {
Line 3for (i=1;i<=length($0);i++)
Line 4 {ch=substr($0,i,1)
Line 5if (ch==sep)(inside-!inside}
Line 6if (inside&&ch=="|")
Line 7ch=","
Line 8 printf("%s".ch)
Line 9}
Line 10printf("\n")
Line 11}'>$out_location/aci_10temp

i am not sure why in line 1 is BACI_1000| with a pipe is referred instead of only ACI_1000
line 2 : what is SEP i know IFS is used for field separator ..is it same..also same line why is back slash used before curly brackets
line3:think it searches for lenght of column what does $0 refer here.. i know it refers to command itself in general but not clear
line 4:check for length of column in field 1
line 5:did not understand...(what is inside?)
line 6:did not understand
line 7: did not understand
line 8:does it print the column after removing quotes
 

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LEARN ABOUT DEBIAN

logtop

LOGTOP(1)						      General Commands Manual							 LOGTOP(1)

NAME

       logtop - Realtime log line rate analyser

SYNOPSIS

       logtop [OPTIONS]

DESCRIPTION

	logtop is a System Administrator tool analyzing line rate on stdin.
	It reads on stdin and print a constantly updated result
	displaying, in columns:
	Line number, count, frequency, and the actual line.

	 $ tail -f FILE | logtop
	is the friendly version of:
	 $ watch 'tail FILE | sort | uniq -c | sort -gr'

OPTIONS

       -s, --size=K
	      Only keep K lines in memory, instead of 10000.

       -q, --quiet
	      Do not display a live view of the data, only display a top at exit.

       -l, --line-by-line=K
	      Print result line by line, in a machine friendly format, K is the number of result to print per line.

		Line by line format is : [%d %f %s	]*

		  %d : Number of occurences
		  %f : Frequency of apparition
		  %s : String (Control chars replaced by dots.

       -i, --interval=K
	      Interval between graphical updates, in seconds. Defaults to 1.

       -h, --help
	      Show summary of options.

       -v, --version
	      Show version of program.

EXAMPLES

       Here are some logtop usage examples.

       tail -f cache.log | grep -o "HIT|MISS" | logtop

       Realtime hit / miss ratio on some caching software log file.

       tail -f access.log | cut -d' ' -f1 | logtop -s 10000

       Realtime most querying IPs on your server, as long as log lines in access.log starts with the client IP.

       tail -f access.log | cut -d' ' -f7 | logtop -s 10000

       Realtime most requested web pages in a NCSA like log file.

       cat auth.log | grep -v "CRON" | grep -o ": .*" | logtop -q -s 100000

       Display a one-shot simple analyse of your auth.log.

SEE ALSO

       watch(1)

AUTHOR

       logtop was written by Julien Palard.

       This manual page was written by Julien Palard <julien@palard.fr>, for the Debian project (and may be used by others).

								  April 16, 2011							 LOGTOP(1)
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