lnx1 1> mysum 1 2 8 10 ^D 21.00000000000000 lnx1 2> mysum < first100 5050.000000000000 lnx1 3> mysum 12 2 8 a 10 b ^D 32.00000000000000 2 invalid inputs lnx1 4> mysum < first100 > mysum_result lnx1 5> more !$ more mysum_result 5050.000000000000