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 2.\" Copyright (c) 2019 Ted Unangst
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16.Dd $Mdocdate$
17.Dt HFCS 1
18.Os
19.Sh NAME
20.Nm hfcs
21.Nd honk filtering and censorship system
22.Sh DESCRIPTION
23The honk filtering and censorship system,
24.Nm hfcs ,
25controls what messages are seen and how they are presented to the user.
26Filter rules are based on a series of matches and actions.
27It is accessed via the
28.Pa filters
29menu item.
30.Pp
31The following match types are possible.
32All nonempty criteria must match.
33.Bl -tag -width include-audience
34.It Ar who
35Match an actor or domain name.
36Matches against
37.Fa Ar actor
38property.
39.It Ar include audience
40Previous match is applied against
41.Fa to
42and
43.Fa cc
44fields as well.
45.It Ar text
46Regular expression match against the post
47.Fa content .
48.It Ar is announce
49Is announced (shared).
50.It Ar announce of
51Limit prevous match to only specified actor or domain name.
52.El
53.Pp
54The following actions may be applied.
55Multiple actions may be applied, but some are subsumed by others.
56.Bl -tag -width tenletters
57.It Ar reject
58Reject this message entirely.
59.It Ar skip media
60Don't include images or attachments.
61.It Ar hide
62Remove this message from most feeds.
63.It Ar collapse
64Show only a short summary with click to view content.
65.It Ar rewrite
66Rewrite message content, using
67.Ar replace
68replacement text.
69.El
70.Pp
71The
72.Ar text
73and
74.Ar rewrite
75fields are case insensitive word anchored regular expressions.
76Specifically, an argument
77.Ql re
78will be automatically rewritten as
79.Ql \\\b(?i:re)\\\b .
80The
81.Ar replace
82text may refer to submatches using $1, etc.
83.Pp
84A post marked sensitive that does not otherwise contain a summary will
85have an invisible summary of
86.Dq unspecified horror
87that can be matched against and will appear if the post is collapsed.
88.Pp
89An optional expiration may be specified as a duration.
90XdYhZm for X days, Y hours, and Z minutes.
91.Sh SEE ALSO
92.Xr honk 1
93.Sh CAVEATS
94Not seeing is not erasing.