Shell Programming and Scripting

cat a1.txt
1
2
3
4
5
6
7
8
9
10

cat a2.txt
1
3
4
6
8
2
5
7
9

sed -e 's/^/a1:/' a1.txt

a1:1
a1:2
a1:3
a1:4
a1:5
a1:6
a1:7
a1:8
a1:9
a1:10

sed -e 's/^/a2:/' a2.txt
a2:1
a2:3
a2:4
a2:6
a2:8
a2:2
a2:5
a2:7
a2:9

$ cat file1
a1:1
a1:2
a1:3
a1:4
a1:5
a1:6
a1:7
a1:8
a1:9
a1:10

$ cat file2
a2:1
a2:3
a2:4
a2:6
a2:8
a2:2
a2:5
a2:7
a2:9

$ awk -F":" 'FNR==NR{A[$2];next}!($2 in A){print $0, "is not there"}' file2 file1
a1:10 is not there

 
while read line
do
value=`echo $line | awk -F":" '{print $2}'` ### taking the second column for a1 file ###
check_value_other_file=`cat a2_2 | grep "$value"` ### checking either that content is present in file a2 or not ####
 
### checking the value for check_value_other_file if it is empty which means a2 doesn't have value present in a1 so then printing that value ###
if [[ -z ${check_value_other_file} ]]
then
echo "value "$line" is NOT present at a1_1"
fi
done < a1_1

value a1:10 is NOT present at a2_2

$ awk -F":" 'FNR==NR{A[$2];next}!($2 in A){print $0, "is not there"}' file2 file1