Shell Programming and Scripting

Hello everybody

Looking for help in comparing two files in Linux(files are big 800MB each).

Example:-

File1 has below data
$ cat file1
5,6,3
2.1.4
1,1,1
8,9,1

File2 has below data
$ cat file2
5,6,3
8,9,8
1,2,1
2,1,4

Need Output as below
8,9,8
1,2,1
1,1,1
8,9,1

tried below awk command but it giving below output which is not correct
$ awk 'NR==FNR{a[$0]++;next} !a[$0]' file2 file1
2.1.4
1,1,1
8,9,1

$ cat vlookup.awk
FNR==NR{
a[$1]=$2
next
}
{ if ($1 in a) {print $1, a[$1]} else {print $1, "NA"} }

awk -f vlookup.awk file2 file1 | column -t
$ awk -f vlookup.awk file2 file1 | column -t
5,6,3
2.1.4 NA
1,1,1 NA
8,9,1 NA

treid below do while loop with grep command but its taking lot of time.

$ cat scp.sh
rm -f newfile.txt
while read line
do
line1=`grep -ie "${line}" file1`
if [ $? -ne 0 ] ; then
echo "$line" >> file2
fi
done <CUDB_REF

./scp.sh
8,9,8
1,2,1

This is correct but taking very long time for big file

Pls suggest better way which is fast.

Double post; continue here.