Собственно, вот:
#!/usr/bin/awk BEGIN { N = 0; X = 0; Y = 0; XY = 0; XX = 0; } /^-?[0-9]/ { N += 1; X += $1; XX += $1*$1; Y += $2; XY += $1*$2; } END { b = (N*XY - X*Y)/(N*XX - X*X); a = (Y - b*X)/N; printf "N = %d, y = %g * x + %g\n", N, b, a }