Question

I have a file that contains data in the following format:

Field 1 Field 2 nCalls duration

My task is to sum the nCalls and duration fields. The code I have written so far is as follows:

cat ${file} |\
while read n1 n2 nCalls nDuration
do
  #sumCalls=$((${sumCalls} + ${nCalls}))
  #sumDuration=$((${sumDuration} + ${nDuration}))
  sumCalls=`expr ${sumCalls} + ${nCalls}`
  sumDuration=`expr ${sumDuration} + ${nDuration}`
  echo "${sumCalls} ${sumDuration}"
  echo -n "${appName} ${sumCalls} ${sumDuration}" > temp.txt
done

tail -n1 temp.txt >> ${outFile}  

Both the statements above do not work. I get syntax errors.

My question is:
1. Where am I going wrong with the above code?
2. Is there a better way to do this than write into and out of files?

Thanks,
Sriram

Answer 1

This is what awk was built for:

cat ${file} | awk '{c = c + $3; d = d + $4} END {print "APPNAME", c, d}'

The following transcript shows it in action:

pax$ export appName=xyz

pax$ echo 'a b 1 2
...> a b 3 4
...> a b 5 6' | awk -vAPPNAME=${appName} '{c=c+$3;d=d+$4}END{print APPNAME,c,d}'
xyz 9 12