Exiftool
Only change the dates in exif information
Sometimes you only want to set the dates, not adjust them, but set them static, but keep the hour/minute/second in the file.
exiftool -m '-DateTimeOriginal<2014:04:05 ${DateTimeOriginal;s/.* //}' '-CreateDate<2014:04:05 ${CreateDate;s/.* //}' '-ModifyDate<2014:04:05 ${ModifyDate;s/.* //}' FILE
Remove all meta data
exiftool -all= --overwrite_original foo.jpg