摘要：bcp中-F和-L的使用
-F就是first, -L就是last
when bcp in, -F, -L indicates the first and last line in the file.
when bcp out, they indicate the first row and last row in table. this is really cute.
you can use -F and -L to bcp in/out partial file/table, or you can use them to do con-currently bcp in