github.com/benhoyt/goawk@v1.8.1/testdata/gawk/subback.awk (about)

     1  BEGIN {
     2      A[0] = "&"
     3      for(i=1;i<=11;i++) {
     4  	A[i] = "\\" A[i-1]
     5      }
     6  ## A[] holds  & \& \\& \\\& \\\\& ...
     7  }
     8  
     9  {
    10      for(i=0; i <= 11 ; i++) {
    11          x = $0 
    12          sub(/B/, A[i], x)
    13  	print i, x
    14      }
    15  }