我有三个文件，如下图：
FILE 1:
DATE PGTO_CRED
20180801 50.00
20180802 150.00
20180803 130.00
20180804 110.00
20180805 200.00
FILE 2:
DATE PGTO_TOTAL
20180801 150.00
20180802 300.00
20180803 200.00
20180804 250.00
20180805 400.00
FILE 3:
DATE PGTO_FEE
20180801 35.00
20180802 10.00
20180803 25.00
20180804 140.00
20180805 135.00
我需要我的输出文件是这样的：
DATE PGTO_CRED PGTO_TOTAL PGTO_FEE
20180801 50.00 150.00 35.00
20180802 150.00 300.00 10.00
20180803 130.00 200.00 25.00
20180804 110.00 250.00 140.00
20180805 200.00 400.00 135.00
如何在 Redhat Linux 上执行此操作？