I have two files. One has a variable as field 1. I am using this to look up a value in another file which has the variable as a record, followed by another record containing the information I want. ie I am looking up 1 to find A or 3 to find C.
1
A
2
B
3
C
I should be able to get this easily with awk using the following line.
awk '{if ($1=="3") A=NR}{ if (NR==(A+1)) print $0}' FILEIN
output should be
C
instead I am getting an output with the first line, then the correct value. ie
1
C
If I just put in the NR value rather than assigning a variable it gives me only the data I want. If I put (A+2) it gives me line 2 and the line I want, so on and so on. Any ideas as to why this is happening
as shelter commented, at beginning the A wasn't assigned by a value, awk will take 0, so 0+1, 0+2... you see why you got the unexpected line.
you don't have to play with NR for your needs, if I understood your requirement right.
try this line:
awk '$1=="3"{getline;print;exit}' file
test with your example:
kent$ echo "1
A
2
B
3
C"|awk '$1=="3"{getline;print;exit}'
C
If you just want to fix the problem in your code, you add a &&A, like:
awk '{if ($1=="3") A=NR}{ if (NR==(A+1)&&A) print $0}'
and your line could be shorten as:
awk '$1=="3"{A=NR}NR==(A+1)&&A'