On my linux system

$ date --date=31-JAN-2007
Wed Jan 31 00:00:00 CET 2007
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And converted:

$ date --date=31-JAN-2007 +%s
1170198000
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(If you mean seconds since `00:00:00 1970-01-01 UTC' with "epoch seconds" and don't mind using backticks.)