Sieve in brief

Sieve (RFC 5228) is a small language for mail filters that the mail server runs on delivery. A script is a list of commands; most are if rules with a test and actions.

require ["fileinto"];

if header :contains "List-Id" "swift.org" {
    fileinto "Lists/Swift";
    stop;
}

• require names the extensions a script uses, e.g. fileinto, vacation, imap4flags, variables.
• Tests: header, address, envelope, size, exists, combined with allof, anyof and not.
• Match types: :is, :contains, :matches (wildcards), :regex (if the server supports it).
• Actions: keep, fileinto, redirect, discard, reject, vacation, stop.

Standards: RFC 5228 (opens in new window) (Sieve), RFC 5804 (opens in new window) (ManageSieve), RFC 5230 (opens in new window) (vacation), RFC 5232 (opens in new window) (imap4flags), RFC 5229 (opens in new window) (variables).