.Dd May 4, 2020
.Dt MTHREAD 1
.Os
.Sh NAME
.Nm mthread
.Nd arrange messages into discussions
.Sh SYNOPSIS
.Nm
.Op Fl vpr
.Op Fl S Ar msg
.Op Ar msgs\ ...
.Sh DESCRIPTION
.Nm
groups messages together in parent/child relationships, based on
which messages are replies to which others.
.Po
See
.Xr mmsg 7
for the message argument syntax.
.Pc
.Pp
If no messages are specified,
.Nm
will read filenames from the standard input,
or use the default sequence if used interactively.
.Pp
.Nm
prints the threaded messages separated by newlines and
indented according to their depth in the message tree.
Unresolved Message-IDs are printed as-is.
.Pp
The options are as follows:
.Bl -tag -width Ds
.It Fl v
Do not prune unresolved Message-IDs at the top-level.
.It Fl p
With
.Fl S ,
only add parents, not unrelated subthreads.
.It Fl r
Sort the top-level threads in reverse order (newest threads first).
.It Fl S Ar msg
Treat
.Ar msg
as optional message(s) that will be added to threads only if they
are referenced.
Threads where all messages are optional are suppressed.
You can use
.Fl S
to add an outbox folder, for example,
completing threads where your replies were missing.
.El
.Sh EXIT STATUS
.Ex -std
.Sh SEE ALSO
.Xr mmsg 7
.Pp
.Lk https://www.jwz.org/doc/threading.html "Message threading"
.Sh AUTHORS
.An Leah Neukirchen Aq Mt leah@vuxu.org
.Sh LICENSE
.Nm
is in the public domain.
.Pp
To the extent possible under law,
the creator of this work
has waived all copyright and related or
neighboring rights to this work.
.Pp
.Lk http://creativecommons.org/publicdomain/zero/1.0/