| VF1(1) | General Commands Manual | VF1(1) |
vf1 — command line
gopher client
vf1 |
[-h] [--bookmarks]
[--debug] [--tls]
[url ...] |
vf1 is an interactive command line gopher
client. It presents a prompt to the user, who can then enter commands to
perform actions.
Only a small number of commands are needed to get around, and most of them can be abbreviated to one or two chars, so with practice very quick navigation of gopherspace is possible. See the COMMANDS section for more details.
The options are as follows:
-h,
--help--bookmarks--debug--tlstour.All vf1 commands are listed below. Most
commands operate on an implicit operand from the very limited internal state
which vf1 maintains.
This state includes the “lookup,” which is a list of
items (locations) in Gopherspace with numeric indices attached. Indices
begin from 1. Upon startup, the lookup is empty. Whenever a gopher menu is
visited, the contents of that menu become the contents of the lookup,
replacing any previous contents. Some commands, such as
search, history, or
links overwrite the lookup with their results. At
any time, the lookup can be reset to the contents of the most recently
visited gopher menu with the ls command.
In addition to the lookup, vf1 is aware of
exactly one active item (the item the user is currently viewing). Usually,
the active item is one of the items in the lookup, and if so
vf1 knows its index.
Most vf1 commands operate on either the
lookup, or the active item.
In addition to the commands listed below, users can enter a
numeric index. vf1 will then navigate to the
corresponding item in the lookup, and that item will become the active
item.
a,
addb,
backbb,
blackboxbm,
book, bookmarkscatexitf,
foldfo,
forwardg,
go url |
markhandler
[mimetype program]help
[command]h,
hist, historyl,
lessli,
linksls
[-l]ls
-l the listing will include the URL of each menu item.m,
mark [mark]go command to return to the current item
later. Lists all defined marks when no argument is given.n,
nextp,
prev, previousq,
quitr,
reloadroots,
save [filename]save saves the
current item with an automagic filename derived from its gopher selector.
save filename saves the
current item with the specified filename. save
n saves the item at lookup index n with an
automagic filename. save n
filename saves the item at lookup index n with the
specified filename./,
se, search
patternset
[option value]tlst,
tour [item ...]tour 1 2 3 4,
or consecutive ranges like tour
1-4. All items in the lookup can be added with
tour *. Items not in the
lookup can be added by their URL with tour
url. The current tour queue can be listed with
tour ls and scrubbed with
tour clear.up,
uurlv,
veronica [query]vf1 uses external programs as
“handlers” to present different gopherspace content to the
user. Even when visiting a plain text file with item type 0,
vf1 uses (by default) the unix command
cat(1) to display that file on the screen, rather than
using a Python
print()
call. Users have full control over which external programs are used for
different content, so the user experience can be customised to taste.
Handlers are assigned on the basis of MIME types. The gopher
protocol has no concept of MIME type, so vf1 assigns
each item a MIME type itself in the manner described in the section
MIME type assignment
below.
A list of the current handler assignments can be viewed at any
time by running the handler command. The default
handlers that ship with vf1 are:
| MIME type | handler |
| application/pdf: | xpdf %s |
| audio/mpeg: | mpg123 %s |
| audio/ogg: | ogg123 %s |
| image/*: | feh %s |
| text/*: | Ta cat %s |
| text/html: | lynx -dump -force_html %s |
The handler command can be used to change
these handlers, or set handlers for new MIME types. For example, users who
prefer w3m(1) over lynx(1) for handling
HTML content could run:
VF-1> handler text/html w3m -dump
%sThe specified handler will be run as a shell command, with the temporary file containing the content of the current gopher item replacing any occurrences of %s. Pipe syntax can be used to pass gopher content through multiple text filters to achieve the desired appearance.
The ‘*’ wildcard can be used
when specifying handler MIME types, e.g.
‘image/*’ allows using a single
program to handle any kind of image. Handlers without wildcards take
precedence over handlers with wildcards. In other words, if one handler is
specified for ‘image/jpeg’ and a
different handler for ‘image/*’, the
‘image/jpeg’ handler will be used for
JPEGs and the ‘image/*’ handler will
be used for all other images.
vf1 assigns MIME types to gopher items as
follows:
text/plain’text/html’image/gif’For all other item types, vf1 attempts to
guess a MIME type from the file extension of the last component of the
selector, using the ‘mimetypes’ module
from the Python standard library. This usually results in a reliable
identification assuming the file has an extension and the author of the
gopher content is not being deliberately deceptive.
If the selector has no file extension, or the extension is not
recognised by the ‘itemtypes’ module,
vf1 will use the unix program
file(1) to attempt to guess a MIME type by actually
inspecting the content of the file.
In accordance with the idea that gopher item types, which are a
standard part of the protocol, should take precedence over any other attempt
at inferring MIME type, which is not a standard part of the protocol, if an
item in gopherspace is listed with itemtype
‘I’ or
‘s’ and one of the above methods
returns a MIME type which does not begin with
‘image/’ or
‘sound/’ respectively,
vf1 will default to
‘image/jpeg’ or
‘audio/mpeg’ respectively. This should
only happen in highly unusual circumstances and suggests a poorly or
maliciously configured gopher server.
vf1 attempts to decode the content
received for any text-based item types (e.g. 0, 1, 7, h) as UTF-8. Most
content in gopherspace is ASCII-encoded, and since UTF-8 is backward
compatible with ASCII, this will generally “just work”. If the
received content
cannot
be decoded as UTF-8, one of two possible things will happen:
If the ‘chardet’ Python
module is installed, vf1 will use it to attempt to
automatically detect the encoding used and decode the text appropriately.
Note that pip etc. will not install
‘chardet’ automatically when
installing vf1, as vf1 does
not formally depend on ‘chardet’. It
uses it opportunistically, so that it can still be easily installed and used
on systems where ‘chardet’ is not or
cannot be installed.
If ‘chardet’ is not
installed, or if ‘chardet’ cannot
identify an encoding with confidence exceeding 0.5,
vf1 will attempt to fall back to a single,
user-specified alternative encoding. This encoding can be set as
follows:
VF-1> set encoding
koi8-rThe default fall back encoding is iso-8559-1, which is used by the popular gopher site floodgap.com. Users who routinely visit gopher sites encoded with some other encoding may consider using an RC file (see below) to automatically set the alternative encoding at start up.
vf1 supports TLS connections. This is an
experimental feature, and TLS connections are not supported by the majority
of gopher servers. As such, TLS support must be explicitly activatd by using
the command to enable TLS mode (aka "Battloid mode"). When TLS
mode is enabled,
all gopher
requests will be made over TLS, so most requests will fail when a connection
to the server cannot be established. TLS mode must be explicitly deactivated
to resume browsing unencrypted gopherspace.
The following miscellaneous settings can be adjusted with the command.
debugencodingipv6vf1 will preferentially attempt to
connect to gopher servers via IPv6 if a AAAA DNS record is found. If the
IPv6 connection fails, vf1 will automatically
retry with IPv4. Default value is true.timeoutadd to add the current URL to
the bookmark list.vf1 will search for a file with one
of these names, a so-called RC file (see below).The names are listed above
in order of preference and vf1 will stop after the
first one it finds, e.g. if both
~/.config/vf1/vf1rc and a
~/.vf1rc exist then then
~/.vf1rc will be ignored.If an RC file is found, each line of the file will be executed as
a vf1 command before the prompt is displayed.This
allows users to script certain commands that should be run every time
vf1 is started. This permits, for example:
handler commands in the RC file.set commands in the RC
file.go command in the RC file.tour commands in the RC file.See the vf1-turorial(7) for a comprehensive
introduction to the work flow of vf1
Start vf1:
vf1Start vf1 and immediately open to bookmark
list:
vf1 --bookmarksVisit the zaibatsu:
vf1
zaibatsu.circumlunar.spacevf1 is a gopher client conforming to RFC
1436
⟨https://tools.ietf.org/html/rfc1436⟩.
vf1 is named after the VF-1 Valkyrie
aircraft from the classic '80s anime series Super Dimension Fortress
Macross, in recognition of the role that the SDF Public Access Unix system
⟨gopher://sdf.org⟩,
named after the same series, has played in keeping Gopherspace alive in the
21st century.
Solderpunk
<solderpunk@sdf.org>
Alex Schroeder
<alex@gnu.org>
Joseph Lyman
<tfurrows@sdf.org>
Adam Mayer
⟨https://github.com/phooky⟩
Paco Esteban
<paco@onna.be>
| August 31, 2019 | All Operating Systems |