trn.1

早期freebsd实现

Leaves you at the \*(L"What next?\*(R" prompt.
.Ip j 8
Junk the current article.
Mark it read and go to the end of the article.
.Ip ^L 8
Refresh the screen.
.Ip X 8
Refresh the screen and decrypt as a rot13 message.
.Ip b 8
Back up one page.
.Ip t 8
Display the entire article tree, including its associated subjects, and
continue reading.
If the group is not currently threaded, it will be threaded first.
.Ip gpattern 8
Goto (search forward for)
.I pattern
within current article.
Note that there is no space between the command and the pattern.
If the pattern is found, the page containing the pattern will be displayed.
Where on the page the line matching the pattern goes depends on the value
of the
.B \-g
switch.
By default the matched line goes at the top of the screen.
.Ip G 8
Search for g pattern again.
.Ip ^G 8
This is a special version of the \*(L'g\*(R' command that is for skipping
articles in a digest.
It is equivalent to setting \*(L"\-g4\*(R" and then executing the command
\*(L"g^Subject:\*(R".
.Ip TAB 8
This is another special version of the \*(L'g\*(R' command that is for
skipping inclusions of older articles.
It is equivalent to setting \*(L"\-g4\*(R" and then executing the command
\*(L"g^[^c]\*(R", where \fIc\fR is the first character of the last line
on the screen.
It searches for the first line that doesn't begin with the same character
as the last line on the screen.
.Ip !command 8
Escape to a subshell.
.PP
The following commands skip the rest of the current article, then behave just
as if typed to the \*(L"What next?\*(R" prompt at the end of the article.
See the documentation at the article selection level for these commands.
.Sp	
    # $ & / = ? A c C f F k K T ^K J , m M r R ^R u U v Y ^
.br
    p P ^P - < > [ ] { } number
.br
    range{,range} command{:command}
.Sp
The following commands also skip to the end of the article, but have the
additional effect of marking the current article as read:
.Sp
    n N ^N e s S | w W
.Sp
.Sh "Miscellaneous facts about commands"
An \*(L'n\*(R' typed at either the \*(L"Last newsgroup\*(R" prompt or a
\*(L"Last article\*(R" prompt will cycle back to the top of the newsgroup
or article list, whereas a \*(L'q\*(R' will quit the level.
(Note that \*(L'n\*(R' does not mean \*(L"no\*(R", but rather
\*(L"next\*(R".)
A space will of course do whatever is shown as the
default, which will vary depending on whether
.I trn
thinks you have more articles or newsgroups to read.
.PP
The \*(L'b\*(R' (backup page) command may be repeated until the beginning of
the article is reached.
If
.I trn
is suspended (via a ^Z), then when the job is resumed, a refresh (^L) will
automatically be done (Berkeley-type systems only).
If you type a command such as \*(L'!\*(R' or \*(L's\*(R' which takes you
from the middle of the article to the end, you can always get back into the
middle by typing \*(L'^L\*(R'.
.PP
In multi-character commands such as \*(L'!\*(R', \*(L's\*(R', \*(L'/\*(R',
etc, you can interpolate various run-time values by typing escape and a
character.
To find out what you can interpolate, type escape and \*(L'h\*(R', or check
out the single character % substitutions for environment variables in the
Interpretation and Interpolation section, which are the same.
Additionally, typing a double escape will cause any % substitutions in the
string already typed in to be expanded.
.Sh "The Tree Display"
When reading a threaded newsgroup,
.I trn
displays a character representation of the article tree in the upper right
corner of the header.
For example, consider the following display:
.Sp
.nf
.in +4n
(1)+-(1)--(\fI2\fP)--\fI[2]\fP
\h'\w'(1)'u'|-(1)+-<3>
\h'\w'(1)'u'|\h'\w'-(1)'u'\\-[1]
\h'\w'(1)'u'\\-(1)+-[1]--[1]
\h'\w'(1)+-(1)'u'\\-[1]
.in -4n
.fi
.Sp
This tree represents an initial article that has three direct replies
(the second column with three (1)'s).
Each reply has further replies branching off from them.
In two cases the subject line was altered in the reply, as indicated
by the increasing numbers.
.PP
The third subject is not selected for reading, as indicated by the <>'s.
Note you can always forcefully visit an unselected article with \*(L'N\*(R'
and \*(L'P\*(R' as well as the thread-navagation commands (which are
typically macro'ed to the arrow keys on your keypad).
.PP
When there is only one subject associated with a thread, all the nodes
are marked with the number 1.
When the first subject change arrives, it is marked with the number 2,
and so on.
If you were to look at this thread in the thread selector, the three
subjects associated with it would be listed in the same order as the
ascending digits.
In those rare cases where more than 9 subjects are associated with each
thread, the nodes are marked with the letters A-Z, and then by a-z.
.PP
The articles that have already been read are enclosed in ()'s,
Unread articles are displayed in []'s, and unread-but-unselected articles
are displayed in <>'s.
The currently displayed article has its entire node highlighted in the
display.
The previously displayed article has only its number highlighted.
If the group has not been completely threaded yet, some articles will
appear as (?) until trn can determine if the referenced article truly
exists or not.
If you visit such an article and wait for trn to finish threading the
group, the screen will refresh as soon as the presence or absence of
the article is determined.
.Sh "Options"
.I Trn
has a nice set of options to allow you to tailor the interaction
to your liking.
(You might like to know that the author swears by
\*(L"\-x6ms \-e \+m \-S -XX -N -B -p\*(R".)
These options may be set on the command line, via the TRNINIT
environment variable, via a file pointed to by the TRNINIT variable, or
from within
.I trn
via the & command.
Options may generally be unset by typing \*(L"+switch\*(R".
Options include:
.TP 5
.B \-a
causes trn to always thread the unread articles on entry to a group.
Without this option trn may enter a group in a partially-threaded
state and process the unthreaded articles in the background.
The down side of this is that the tree display may not be complete when
it is first displayed and you may start out at an odd position in the
first thread's article tree.
.TP 5
.B \-A
tells trn to attempt to create some default macros that will map your
arrow keys to useful trn functions (this is the default).
Use 
.B +A
to turn this behavior off.
.TP 5
.B \-b
will force trn to read each thread in a breadth-first order, rather than
depth-first.
.TP 5
.B \-B
will turn on a spinner that twirls when trn is doing background
article-processing.
A gizmo for those interested in what's going on behind the scenes.
.TP 5
.B \-c
checks for news without reading news.
If a list of newsgroups is given on the command line, only those newsgroups
will be checked; otherwise all subscribed-to newsgroups are checked.
Whenever the
.B \-c
switch is specified, a non-zero exit status from
.I trn
means that there is unread news in one of the checked newsgroups.
The
.B \-c
switch does not disable the printing of newsgroups with unread news;
this is controlled by the
.B \-s
switch.
(The
.B \-c
switch is not meaningful when given via the & command.)
.TP 5
.B \-C<number>
tells
.I trn
how often to checkpoint the
.IR .newsrc ,
in articles read.
Actually, this number says when to start thinking about doing a checkpoint
if the situation is right.
If a reasonable check-pointing situation doesn't arise within 10 more
articles, the
.I .newsrc
is check-pointed willy-nilly.
.TP 5
.B \-d<directory name>
sets the default save directory to something other than ~/News.
The directory name will be globbed (via csh) if necessary (and if possible).
Articles saved by
.I trn
may be placed in the save directory or in a subdirectory thereof depending
on the command that you give and the state of the environment variables
SAVEDIR and SAVENAME.
Any KILL files (see the K command in the Article Selection section)
also reside in this directory and its subdirectories, by default.
In addition, shell escapes leave you in this directory.
.TP 5
.B \-D<flags>
enables debugging output.
See common.h for flag values.
Warning: normally
.I trn
attempts to restore your
.I .newsrc
when an unexpected signal or internal error occurs.
This is disabled when any debugging flags are set.
.TP 5
.B \-e
causes each page within an article to be started at the top of the screen,
not just the first page.
(It is similar to the
.B \-c
switch of
.IR more (1).)
You never have to read scrolling text with this switch.
This is helpful especially at certain baud rates because you can start reading
the top of the next page without waiting for the whole page to be printed.
It works nicely in conjunction with the
.B \-m
switch, especially if you use half-intensity for your highlight mode.
See also the
.B \-L
switch.
.TP 5
.B \-E<name>=<val>
sets the environment variable <name> to the value specified.
Within
.IR trn ,
\*(L"&\-ESAVENAME=%t\*(R" is similar to \*(L"setenv SAVENAME '%t'\*(R" in
.IR csh ,
or \*(L"SAVENAME='%t'; export SAVENAME\*(R" in
.IR sh .
Any environment variables set with
.B \-E
will be inherited by subprocesses of
.IR trn .
.TP 5
.B \-f
will make trn avoid various sleep calls and the prompt after the processing
of the memorized commands that are intended to allow you time to read a
message before the screen clears.
This allows the advanced user to cruise along a little faster at the
expense of readability.
The \-t (terse) option turns on -f by default, but you can override this
by specifying \+f after the \-t option.
.TP 5
.B \-F<string>
sets the prefix string for the \*(L'F\*(R' follow-up command to use in
prefixing each line of the quoted article.
For example, \*(L"\-F<tab>\*(R" inserts a tab on the front of each line
(which will cause long lines to wrap around, unfortunately),
\*(L"\-F>>>>\*(R" inserts \*(L">>>>\*(R" on every line, and
\*(L"\-F\*(R" by itself causes nothing to be inserted, in case you want to
reformat the text, for instance.
The initial default prefix is \*(L">\*(R".
.TP 5
.B \-g<line>
tells
.I trn
which line of the screen you want searched-for strings to show up on when
you search with the \*(L'g\*(R' command within an article.
The lines are numbered starting with 1.
The initial default is \*(L"\-g1\*(R", meaning the first line of the screen.
Setting the line to less than 1 or more than the number of lines on the screen
will set it to the last line of the screen.
.TP 5
.B \-G
selects the "fuzzy" processing on the go command when you don't type in a
valid group name.
With this option on trn will attempt to find the group you probably meant
to type, but it can be a little slow about it, so it's not on by default.
.TP 5
.B \-h<string>
hides (disables the printing of) all header lines beginning with
.I string.
For instance, \-hexp will disable the printing of the \*(L"Expires:\*(R" line.
Case is insignificant.
If <string> is null, all header lines except Subject are hidden, and you
may then use
.B +h
to select those lines you want to see.
You may wish to use the baud-rate switch modifier below to hide more lines
at lower baud rates.
.TP 5
.B \-H<string>
works just like
.B \-h
except that instead of setting the hiding flag for a header line, it sets
the magic flag for that header line.
Certain header lines have magic behavior that can be controlled this way.
At present, the following actions are caused by the flag for the particular
line:
the Date line prints the date in local time if the group is threaded;
the From line will only print the commented portion of the user name;
the Newsgroups line will only print when there are multiple newsgroups;
the Subject line will be underlined and (when threaded) the
keyword \*(L'Subject:\*(R' is replaced by its subject number (e.\|g. [1]);
and the Expires line will always be suppressed if there is nothing on it.
In fact, all of these actions are the default, and you must use
.B +H
to undo them.
.TP 5
.B \-i=<number>
specifies how long (in lines) to consider the initial page of an
article \*(-- normally this is determined automatically depending on baud rate.
(Note that an entire article header will always be printed regardless of the
specified initial page length.
If you are working at low baud rate and wish to reduce the size of the
headers, you may hide certain header lines with the
.B \(bsh
switch.)
.TP 5
.B \-I
tells trn to append all new, unsubscribed groups to the end of the .newsrc.
.TP 5
.B \-j
forces trn to leave control characters unmolested in messages.
.TP 5
.B \-l
disables the clearing of the screen at the beginning of each
article, in case you have a bizarre terminal.
.TP 5
.B \-L
tells
.I trn
to leave information on the screen as long as possible by not blanking
the screen between pages, and by using clear to end-of-line.
(The