C:\Steve\Dev\PerlMonks\P-2013-09-16@0043-TwoKeySort>perl TwoKeySort.pl

C:\Steve\Dev\PerlMonks\P-2013-09-16@0043-TwoKeySort>type test1.dat
key1  key2  ndnjfgdsjfjjkjjfjf...
key1  key2  kdfkjdfgdfugbjndkfgkjgndkjfjkd
key43 key21 sdkjfhdghdbgbd
key1  key3  jujdejnsduhffnjj
key2  key2  jhzezhdjjf...

C:\Steve\Dev\PerlMonks\P-2013-09-16@0043-TwoKeySort>type test1.dat-output.dat
key1  key2  ndnjfgdsjfjjkjjfjf...
key1  key2  kdfkjdfgdfugbjndkfgkjgndkjfjkd
key1  key3  jujdejnsduhffnjj
key2  key2  jhzezhdjjf...
key43 key21 sdkjfhdghdbgbd

C:\Steve\Dev\PerlMonks\P-2013-09-16@0043-TwoKeySort>