The Times That find Finds (Unix Power Tools, 3rd Edition)

9.7. The Times That find Finds

The times that go with the find operators -mtime , -atime, and -ctime often aren't documented very well. The times are in days:

A number with no sign, for example, 3 (as in -mtime 3 or -atime 3), means the 24-hour period that ended exactly 3 days ago (in other words, between 96 and 72 hours ago).
A number with a minus sign (-) refers to the period since that 24-hour period. For example, -3 (as in -mtime -3) is any time between now and 3 days ago (in other words, between 0 and 72 hours ago).
Naturally, a number with a plus sign (+) refers to the period before that 24-hour period. For example, +3 (as in -mtime +3) is any time more than 3 days ago (in other words, more than 96 hours ago).

Got that? Then you should see that -atime -2 and -atime 1 are both true on files that have been accessed between 48 and 24 hours ago. (-atime -2 is also true on files accessed 24 hours ago or less.)

For more exact comparisons, use find -newer with touch (Section 9.8).

-- JP