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Full Discussion: Variable scope in bash
Top Forums Shell Programming and Scripting Variable scope in bash Post 302589363 by methyl on Wednesday 11th of January 2012 12:04:45 PM
Old 01-11-2012
The script is not slow for its content.
The "sar -d 30 4" statement will take 2 minutes (sample interval of thirty seconds times the four iterations). On my test the script took 2 mins 3 secs.

The process to fish out the Average lines can be improved such that we only read $TEMP1 once.

Code:
#!/bin/sh
PATH=/usr/bin:/usr/sbin:/sbin; export PATH
TEMP1="/tmp/raw-sar-output.txt$$"
TEMP2="/tmp/sorted-sar-output.txt$$"
CONT=0
sar -d 30 4 > $TEMP1
grep \^"Average" $TEMP1 | awk '{ print $5,$2 }' | sort -k 1n,1 > $TEMP2
if [ -s "$TEMP2" ]
then
   while read file;
   do
      IO=`echo $file | awk '{ print $1 }'`
      TMP_VAL=`echo $file | awk '{ print $1 }'`
      CONT=`expr $CONT + $TMP_VAL`
   echo CONT = $CONT
   done < $TEMP2
   #Echo Result
   echo $CONT
else
   rm -f $TEMP1 $TEMP2 2>/dev/null
   exit 1
fi
rm -f $TEMP1 $TEMP2 2>/dev/null
exit 0


If performance was really important, there is no need for the workfile $TEMP1 and (as Corona688 notes) the maths can be done in awk.

The other issue with your script is possibly the design. Field 5 in "sar" is the Number of Read+Write data transfers PER SECOND. Over the sample period of just 2 minutes you need some decent level of disc activity to get this figure above zero.

Finally the question I should have asked first:
Please explain the statement "execution is too slow and causes problems to the use I need it for".


(You are aware that unix systems can be configured to accumulate "sar" statistics automatically all day every day)?
 

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LEARN ABOUT OPENSOLARIS

sadc

sar(1M) 						  System Administration Commands						   sar(1M)

NAME

       sar, sa1, sa2, sadc - system activity report package

SYNOPSIS

       /usr/lib/sa/sadc [t n] [ofile]

       /usr/lib/sa/sa1 [t n]

       /usr/lib/sa/sa2 [-aAbcdgkmpqruvwy] [-e time] [-f filename]
	    [-i sec] [-s time]

DESCRIPTION

       System  activity  data  can  be	accessed at the special request of a user (see sar(1)) and automatically, on a routine basis, as described
       here. The operating system contains several counters that are incremented as various system actions occur. These include counters  for  CPU
       utilization,  buffer  usage, disk and tape I/O activity, TTY device activity, switching and system-call activity, file-access, queue activ-
       ity, inter-process communications, and paging. For more general system statistics, use iostat(1M), sar(1), or vmstat(1M).

       sadc and two shell procedures, sa1 and sa2, are used to sample, save, and process this data.

       sadc, the data collector, samples system data n times, with an interval of t seconds between samples, and writes in binary format to  ofile
       or to standard output. The sampling interval t should be greater than 5 seconds; otherwise, the activity of sadc itself may affect the sam-
       ple. If t and n are omitted, a special record is written. This facility can be used at system boot  time,  when	booting  to  a	multi-user
       state,  to mark the time at which the counters restart from zero. For example, when accounting is enabled, the svc:/system/sar:default ser-
       vice writes the restart mark to the daily data file using the command entry:

	 su sys -c "/usr/lib/sa/sadc /var/adm/sa/sa'date +%d'"

       The shell script sa1, a variant of sadc, is used to collect and store data in the binary file /var/adm/sa/sadd, where  dd  is  the  current
       day.  The  arguments  t and n cause records to be written n times at an interval of t seconds, or once if omitted. The following entries in
       /var/spool/cron/crontabs/sys will produce records every 20 minutes during working hours and hourly otherwise:

	 0 * * * 0-6 /usr/lib/sa/sa1
	 20,40 8-17 * * 1-5 /usr/lib/sa/sa1

       See crontab(1) for details.

       The shell script sa2, a variant of sar, writes a daily report in the file /var/adm/sa/sardd. See the  OPTIONS  section  in  sar(1)  for	an
       explanation  of the various options. The following entry in /var/spool/cron/crontabs/sys will report important activities hourly during the
       working day:

	 5 18 * * 1-5 /usr/lib/sa/sa2 -s 8:00 -e 18:01 -i 1200 -A

FILES

       /tmp/sa.adrfl

	   address file

       /var/adm/sa/sadd

	   Daily data file

       /var/adm/sa/sardd

	   Daily report file

       /var/spool/cron/crontabs/sys

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Availability		     |SUNWaccu			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       crontab(1), sag(1), sar(1), svcs(1), timex(1), iostat(1M), svcadm(1M), vmstat(1M), attributes(5), smf(5)

NOTES

       The sar service is managed by the service management facility, smf(5), under the service identifier:

	 svc:/system/sar

       Administrative actions on this service, such as enabling, disabling, or requesting restart, can be performed  using  svcadm(1M).  The  ser-
       vice's status can be queried using the svcs(1) command.

SunOS 5.11							    20 Aug 2004 							   sar(1M)
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