Search Mailogs by date & email

==== Required information ====
- iRedMail version: v2.1.1 (LDAP)
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): LDAP
- Linux/BSD distribution name and version: Ubuntu 12.04 LTS
- Related log if you're reporting an issue:
====

Hi,

Good day to all,

Well i need some basic commands to find mailogs by date and by email address.

I'm just using this command to search:

tail -1000 /var/log/mail.log

&

cat  /var/log/mail.log | grep emailaddress

and also how can i increase the mailogs number of days?

Thanks in advance

regards,
Shaik