Shell Programming and Scripting

file 1
 0.00   5.905 
 0.05   5.740 
 0.10   5.570 
 0.15   5.440 
 0.20   5.310 
 0.25   5.185 
 0.30   5.075 
 0.35   5.897 
 0.40   6.883 

file 2
 0.00   8.510 
 0.05   8.130 
 0.10   7.730 
 0.15   7.390 
 0.20   7.120 
 0.25   6.850 
 0.30   9.877 
 0.35   9.463 
 0.40   9.063 

file 3 
 0.00   5.515 
 0.05   5.375 
 0.10   5.300 
 0.15   5.200 
 0.20   4.710 
 0.25   5.280 
 0.30   5.147 
 0.35   5.055 
 0.40   4.968

 0.00   median of (5.905, 8.510, 5.515) 
 0.05   median of (5.740, 8.130, 5.375) 
 0.10   median of (5.570, 7.730, 5.300) 
 0.15   median of (5.440, 7.390, 5.200) 
 0.20   median of (5.310, 7.120, 4.710) 
 0.25   median of (5.185, 6.850, 5.280) 
 0.30   median of (5.075, 9.877, 5.147) 
 0.35   median of (5.897, 9.463, 5.055) 
 0.40   median of (6.883, 9.063, 4.968)

awk '{a[$1] = (a[$1] == "") ? $2 : (a[$1] "|" $2)}
  END {for(x in a)
    {split(a[x], b, "|"); n=asort(b, c);
 if(n % 2 == 1)
   {m = c[int(n /2) + 1]}
 else
   {m = (c[int(n /2)] + c[int(n /2) + 1]) / 2};
 print x, m}}' file* | sort -n -k1