You need to use the find command. Each file has three time stamps, which record the last time that certain operations were performed on the file:

[a] access (read the file’s contents) – atime

[b] change the status (modify the file or its attributes) – ctime

[c] modify (change the file’s contents) – mtime

You can search for files whose time stamps are within a certain age range, or compare them to other time stamps.

You can use -mtime option. It returns list of file if the file was last accessed N*24 hours ago. For example to find file in last 2 months (60 days) you need to use -mtime +60 option.

• -mtime +60 means you are looking for a file modified 60 days ago.
• -mtime -60 means less than 60 days.
• -mtime 60 If you skip + or – it means exactly 60 days.

So to find text files that were last modified 60 days ago, use
$ find /home/you -iname "*.txt" -mtime -60 -print

Display content of file on screen that were last modified 60 days ago, use
$ find /home/you -iname "*.txt" -mtime -60 -exec cat {} \;

Count total number of files using wc command
$ find /home/you -iname "*.txt" -mtime -60 | wc -l

You can also use access time to find out pdf files. Following command will print the list of all pdf file that were accessed in last 60 days:
$ find /home/you -iname "*.pdf" -atime -60 -type -f

List all mp3s that were accessed exactly 10 days ago:
$ find /home/you -iname "*.mp3" -atime 10 -type -f

There is also an option called -daystart. It measure times from the beginning of today rather than from 24 hours ago. So, to list the all mp3s in your home directory that were accessed yesterday, type the command
$ find /home/you -iname "*.mp3" -daystart -type f -mtime 1

Where,

• -type f – Only search for files and not directories

-daystart option

The -daystart option is used to measure time from the beginning of the current day instead of 24 hours ago. Find out all perl (*.pl) file modified yesterday, enter:

find /nas/projects/mgmt/scripts/perl -mtime 1 -daystart -iname "*.pl"

You can also list perl files that were modified 8-10 days ago, enter:
To list all of the files in your home directory tree that were modified from two to four days ago, type:

find /nas/projects/mgmt/scripts/perl -mtime 8 -mtime -10 -daystart -iname "*.pl"

-newer option

To find files in the /nas/images directory tree that are newer than the file /tmp/foo file, enter:

find /etc -newer /tmp/foo

You can use the touch command to set date timestamp you would like to search for, and then use -newer option as follows

touch --date "2010-01-05" /tmp/foo
# Find files newer than 2010/Jan/05, in /data/images
find /data/images -newer /tmp/foo

Read the man page of find command for more information:
man find

source: cyberciti.biz/faq/howto-finding-files-by-date/