How to compare two files and print the values of both the files which are different

Question

There are 2 files. I need to sort them first and then compare the 2 files and then the difference I need to print the value from File 1 and File 2.

file1:

pair,bid,ask
AED/MYR,3.918000,3.918000
AED/SGD,3.918000,3.918000
AUD/CAD,3.918000,3.918000

file2:

pair,bid,ask
AUD/CAD,3.918000,3.918000
AUD/CNY,3.918000,3.918000
AED/MYR,4.918000,4.918000

Output should be:

pair,inputbid,inputask,outputbid,outtputask
AED/MYR,3.918000,3.918000,4.918000,4.918000

The only difference in 2 files is AED/MYR with different bid/ask rates. How can I print difference value from file 1 and file 2.

I tried using below commands:

nawk -F, 'NR==FNR{a[$1]=$4;a[$2]=$5;next} !($4 in a) || !($5 in a) {print $1 FS a[$1] FS a[$2] FS $4 FS $5}' file1 file2

Result output as below:

pair,bid,ask,bid,ask
AUD/CAD,3.918000,3.918000,3.918000,3.918000
AUD/CHF,3.918000,3.918000,3.918000,3.918000
AUD/CNH,3.918000,3.918000,3.918000,3.918000
AUD/CNY,3.918000,3.918000,3.918000,3.918000
AED/MYR,3.918000,3.918000,4.918000,4.918000

We are still not able to get only the difference.

Answer 1

Could you please try following, written and tested in GNU awk with shown samples.

awk -v header="pair,inputbid,inputask,outputbid,outtputask" '
BEGIN{
  FS=OFS=","
}
FNR==NR{
  arr[$1]=$0
  next
}
($1 in arr) && arr[$1]!=$0{
  val=$1
  $1=""
  sub(/^,/,"")
  if(!found){
    print header
    found=1
  }
  print arr[val],$0
}'  Input_file1  Input_file2

Explanation: Adding detailed explanation for above.

awk -v header="pair,inputbid,inputask,outputbid,outtputask" '  ##Starting awk program from here and setting this to header value here.
BEGIN{                                                         ##Starting BEGIN section of this program from here.
  FS=OFS=","                                                   ##Setting field separator and output field separator as comma here.
}
FNR==NR{                                                       ##Checking condition FNR==NR which will be TRUE when Input_file1 is being read.
  arr[$1]=$0                                                   ##Creating arr with index $1 and keep value as current line.
  next                                                         ##next will skip all further statements from here.
}
($1 in arr) && arr[$1]!=$0{                                    ##Checking condition if first field is present in arr and its value NOT equal to $0
  val=$1                                                       ##Creating val which has current line value in it.
  $1=""                                                        ##Nullifying irst field here.
  sub(/^,/,"")                                                 ##Substitute starting , with NULL here.
  if(!found){                                                  ##Checking if found is NULL then do following.
    print header                                               ##Printing header here only once.
    found=1                                                    ##Setting found here.
  }
  print arr[val],$0                                            ##Printing arr with index of val and current line here.
}' Input_file1  Input_file2                                    ##Mentioning Input_files here.

Answer 2

With bash process substitution, then join and then choosing with awk:

# print header
printf "%s\n" "pair,inputbid,inputask,outputbid,outtputask"
# remove first line from both files, then sort them on first field
# then join them on first field and output first 5 fields
join -t, -11 -21 -o1.1,1.2,1.3,2.2,2.3 <(tail -n +2 file1 | sort -t, -k1) <(tail -n +2 file2 | sort -t, -k1) |
# output only those lines, that columns differ
awk -F, '$2 != $4 || $3 != $5'