Becareful when using the mtime option in find command
A simple command like the following is very handy when finding all the files in the current directory which have been modified within 1 day.
# find -type f -mtime -1
But the above interpretation is simply wrong!
The real meaning of the above command is: Find all the files in the current directory which have been modified less than 2 days.
So if a file is modified before 1.9999999.. day, it still match the above command since the fractional part is ignored.
Try it yourself if you don't believe.