In linux shell, How to cp/rm files by time?
Depending on what you actually want to do, find provides -[acm]time options for finding files by accessed, created or modified dates, along with -newer and -min. You can combine them with -exec to copy, delete, or whatever you want to do. For example:
find -maxdepth 1 -mtime +1 -type f -exec cp '{}' backup \;
Will copy all the regular files in the current directory more than 1 day old to the directory backup (assuming the directory backup exists).