Easiest way - accessed modified will be the same:

    touch -a -m t 201512180130.09 fileName.ext

Where:

    -a = accessed
    -m = modified
    t  = timestamp - use [[CC]YY]MMDDhhmm[.ss] time format
If you wish to use `NOW` just drop the `t` and the timestamp

To verify they are all the same:
`stat fileName.ext`

See: [touch man][1]


  [1]: http://www.unix.com/man-page/linux/1/touch/