Shell Programming and Scripting

$ cat file1
col1 nbr1
col2 nbr2
col3 nbr3
...

$ cat file2
val1 ri1
val2 ri2
val3 ri3

$ cat file3
(val1 - col1) nbr1    (if nbr1=ri1)
(val3 - col3) nbr3    (if nbr3=ri3)

paste file1 file2 | awk '$2==$4{print "("$3" - "$1") "$2}' > file3

 
$ cat file1
3 22
4 33
6 77
$

$ cat file2
1 22
5 77
$

$ cat file3
(3 - 1) 22
$

$ awk 'NR==FNR{a[$2]=$1;next} {print a[$2]-$1,$2}' file1 file2

2 22
1 77

 
$ cat file1
10 1111
20 1112
30 1113
40 1114
60 1116

 
$ cat file2
2 1111
4 1112
7 1114
5 1115

 
$ awk 'NR==FNR{a[$2]=$1;next} {print a[$2]-$1,$2}' file1 file2
8 1111
16 1112
33 1114
-5 1115

 
$ awk 'NR==FNR{a[$2]=$1;next} {print a[$2]-$1,$2}' file1 file2
8 1111
16 1112
33 1114

awk 'NR==FNR{a[$2]=$1;next} 
    a[$2]!="" {print a[$2]-$1,$2}' file1 file2