Shell Programming and Scripting

Can someone please help me with a unix logic for below. I tried to get the desired output by using change capture condition in Datastage but its not working properly. i have two files file1, file2 as below.
file1
file2
For a combination of VEND_NO, CODE values in every row in file1, have to compare AIR_D, OCEAN_D values in file1 with the values in file2 for the same combination of VEND_NO, CODE values. if there is a mismatch, need to replace with the values found in file2. For example, for the combination of VEND_NO=5000315, CODE=CPT in file1, when comparing AIR_D,OCEAN_D values in file1 with file2, there is a mismatch. so these two values should be replaced. output should be as below.

Could this help you ?

Code:

awk 'NR==FNR{a[$2"|"$3]=$1;next}
a[$1"|"$2]{print a[$1"|"$2],$0}' file1 file2  | sort -nk1

Hi Pravin, Thanks a lor for the reply.

If you dont mind , can you pelase explain the logic as i have to add one more column to compare both files ?

Hi JSKOBS,

I tried my best to explain you..., hope this will help you to understand..

NR = This is the number of input records awk has processed since the beginning of the program's execution
FNR = is the current record number in the current file. FNR is incremented each time a new record is read.
It is reinitialized to zero each time a new input file is started.
For a single file, FNR is nothing but NR (line number)
And for more than one file, NR and FNR will be equal for the first processed file,
but on the first line of the second and subsequent files FNR will start from 1 again.
Condition NR==FNR is true for first file only, so statement a[$2"|"$3]=$1;next will be executed for file1.
a[$2"|"$3]=$1 means array "a" with index field #2 and field #3 concatenated with symbol "|" and we assign value of field#1
In your case our array will be

a[5000315|CPT]=1
a[5000315|DUR]=2
a[5000004|DUR]=3
and so on....
next will skips over the rest of the body.
Second line is to process secod file as condition NR==FNR will failed while processing second file.
a[$1"|"$2] = this is if condition checking if field #1 and field #2 from file2 i.e. a[5000004|DUR] is true or false.
While processing first file we have filled the array , so it is true then print the value of a[5000004|DUR] which is 3 and then $0 i.e. complete line of file2.
After that sending this o/p to sort command , to sort numeric and on field1