Using awk to pull specific lines from a file

Question

I have two files, one file is my data, and the other file is a list of line numbers that I want to extract from my data file. Can I use awk to read in my lines file, and the

Answer 1

I had the same problem. This is the solution already posted by Thor:

cat datafile \
| awk 'BEGIN{getline n<"numbers"} n==NR{print; getline n<"numbers"}'

If like me you don't have a numbers file, but it is instead passed on from stdin and you don't want to generate a temporary numbers file, then this is an alternative solution:

cat numbers \
| awk '{while((getline line<"datafile")>0) {n++; if(n==$0) {print line;next}}}'