match index notation of file1 to the index of file2 and pull out matching rows

Question

file1 contains multiple alphabetic sequences:

AETYUIOOILAKSJ
EAYEURIOPOSIDK
RYXURIAJSKDMAO
URITORIEJAHSJD
YWQIAKSJDHFKCM
HAJSUDIDSJSIAJ
AJDHDPFDIXSIBJ
JAQIAUXCNC         


        

Answer 1

With awk + grep pipeline:

awk '{ pat=sprintf("%*s", int($0)-1, ""); gsub(" ", ".", pat); 
       printf "^%s%s\n", pat, substr($0, length) }' file2 | grep -f- file1

The output:

AETYUIOOILAKSJ
RYXURIAJSKDMAO
URITORIEJAHSJD
JAQIAUXCNCVUFO