Sender:

The sender's email address or the name of the sender.

Recipients:

The recipients of the message.

CC:

Only the CC recipients of the message.

BCC:

Only the BCC recipients of the message. Obviously this can only be applied to outgoing filters.

Sender or Recipients:

The sender's email address or the name of the sender or the recipients of the message.

Subject:

The subject line of the message.

Specific Header:

Any header including custom ones.

If a message uses a header more than once, Evolution pays attention only to the first instance, even if the message defines the header differently the second time. For example, if a message declares the Resent-From: header as "engineering@example.com" and then restates it as "marketing@example.com", Evolution filters as though the second declaration did not occur. To filter on messages that use headers multiple times, use a regular expression.

Message Body:

Searches in the actual text of the message.

Expression:

(For programmers only) Match a message according to an expression you write in the Scheme language used to define filters in Evolution.

Free Form Expression:

(For advanced users only) Combine numerous conditions by using a special syntax.

Date sent:

Filters messages according to the date on which they were sent. First, choose the conditions you want a message to meet, such as before a given date or after a given date. Then choose the time. The filter compares the message's time stamp to the system clock when the filter is run, or to a specific time and date you choose from a calendar. You can also have it look for a message within a range of time relative to the filter, such as two to four days ago.

Date received:

This works the same way as the Date Sent option, except that it compares the time you received the message with the dates you specify.

Label:

Messages can have labels of Important, Work, Personal, To Do, or Later. You can set labels with other filters or manually.

Score:

Sets the message score to any whole number greater than 0. You can have one filter set or change a message score, and then set up another filter to move the messages you have scored. A message score is not based on anything in particular: it is simply a number you can assign to messages so other filters can process them.

Size (kB):

Sorts based on the size of the message in kilobytes.

Status:

Filters according to the status of a message. The status can be Replied To, Draft, Important, Read, or Junk.

Follow Up:

Checks whether the message is flagged for follow-up or completed (after a certain date).

Attachments:

Checks whether there is an attachment for the email.

Mailing List:

Filters based on the mailing list the message came from. This filter checks for a variety of common mailing list related headers but might miss messages from some list servers if they use uncommon headers.

Regex Match:

(For programmers only) If you know your way around a regex, or regular expression, this option allows you to search for complex patterns of letters, so that you can find, for example, all words that start with "a" and end with "m", and are between six and fifteen letters long, or all messages that declare a particular header twice. For information about how to use regular expressions, check the man page for the grep command.