Hi,

I have an issue where i need to lookup in a given transaction file and if the same transaction is found in another file, then i need to replace a few columns with some other value.
Finally, the changed and unchanged lines must be printed and stored in the same source file.

for example :

Code:

f1
100
200
300

Code:

f2 (tran number is second field)
1,100,AAA,BBB,X,CCC
5,200,AAA,BBB,Y,CCC
3,400,AAA,BBB,X,CCC

output should be

Code:

1,100_P,AAA,BBB,X,CCC
5,200_T,AAA,BBB,Y,CCC
3,400,AAA,BBB,X,CCC

as you can see, only 1st and 2nd record have the matching tran from f1. hence they are changed, record 3 will remain as is.

I have done the following but its a very direct approach and takes a huge amount of time.

Code:

cp main_input.txt tmp1.txt;
while read tran_num
do 
    awk  'BEGIN{FS=","; OFS=","} { if ( $2=='${tran_num}' && $5 == "X")  {$2=$2"_P";print}  else if ($2=='${tran_num}' && $5 == "Y") {$2=$2"_T"; print} else {print} }' tmp1.txt > tmp2.txt;
    cp tmp2.txt tmp1.txt;
done < lookup_tran_file.txt
mv tmp1.txt file_input_file.txt

the above works but i dont like the fact that the tmp file is created everytime to preserve the previous modification done by awk. In other words, if f1 will contain 10000 records to be checked, the tmp file will get overwritten 10000 times. This solution is also takin 1-2 hrs to finish depending on the input file size.

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