If you use procmail, there will be an example at:
${PREFIX}/share/autoconvert/procmailrc.example, which helps you to setup
autoconvert as a filter of procmail.
This is a text filter for turning "cvs diff" output into something that
patch(1) understands. This is needed when your version of cvs(1) makes
diffs that confuse patch(1).
A filter program, used to generate text to be
included into C code as #define, provides the conversion
of newlines and quotes into standard C-code text
RubyFilter is a set of Ruby classes built on top of the RubyMail
library that make it easy to write programs that filter and deliver
email to mailboxes.
Pftop is a small, curses-based utility for real-time display of active
states and rule statistics for pf, the packet filter (for OpenBSD)
Pfstat is a small utility that collects packet filter (security/pf) statistics
and produces graphs like mrtg or alike. Samples can be found at the website
below.
The skem utility is a sendmail milter, that checks and maintains a list
of whitelisted, temporary banned, and permanently blacklisted
IP-addresses. How you obtain the entries is up to you, but the included
logwatcher module provides one possibility.
The list is stored in a directory, each entry being a file (usually --
zero sized) or a symlink (usually -- a "broken" one). Such entries are
stored efficiently (within the directory itself) and the directories are
searched using the hash tables on modern file systems. At the same time,
they can be listed, added, and removed with the simple ls(1), touch(1),
and rm(1).
This milter does not itself filter spam, instead it memorizes the
verdicts issued by your other anti-spam defenses to reduce the system
load and resource consumption, by temporarily rejecting the relays
suspected of spamming (banned) and, optionally, by permanently rejecting
the relays "convicted" of spamming (blacklisted).
The idea is to stem the spam from real spam sources, while reducing the
ill effects of false-positives to merely delaying, rather than rejecting
future messages.
WhySynth is a versatile softsynth which operates as a plugin for the
Disposable Soft Synth Interface (DSSI). A brief list of features:
- 4 oscillators, 2 filters, 3 LFOs, and 5 envelope generators per
voice.
- 11 oscillator modes: minBLEP, wavecycle, chorused wavecycle,
asynchronous granular, three FM modes, waveshaper, noise,
PADsynth, and phase distortion.
- 10 filter modes.
- flexible modulation and mixdown options, plus effects.
Text::Decorator is a framework for marking up plain text into various
formats by applying a chain of filters. For instance, you might apply a
filter which will cause URIs in text to be presented as links if the text
is exported as HTML.
scam-backscatter milter
Scam-backscatter prevents spam backscatter (accept and bounce) on
mail servers which don't host mailboxes locally. It validates
mailboxes by verifying the recipient addresses hosted on a different
mail server.