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1 .\" Copyright (c) 2021 Omar Polo <op@omarpolo.com>
2 .\"
3 .\" Permission to use, copy, modify, and distribute this software for any
4 .\" purpose with or without fee is hereby granted, provided that the above
5 .\" copyright notice and this permission notice appear in all copies.
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7 .\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
8 .\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
9 .\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
10 .\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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12 .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
13 .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
14 .Dd $Mdocdate: March 28 2021$
15 .Dt TELESCOPE 1
16 .Os
17 .Sh NAME
18 .Nm telescope
19 .Nd Gemini client
20 .Sh SYNOPSIS
21 .Nm
22 .Bk -words
23 .Op Fl hn
24 .Op Fl c Pa config
25 .Op Ar URL
26 .Ek
27 .Sh DESCRIPTION
28 .Nm
29 is an interactive browser for the Gemini protocol.
30 It is able to process text/gemini and more in general every text/* file.
31 .Nm
32 also features tabs, bookmarks and out-of-band TOFU verification.
33 .Pp
34 The arguments are as follows:
35 .Bl -tag -width tenletters
36 .It Fl h
37 Display version and usage.
38 .It Fl n
39 Configtest mode.
40 Only check the configuration file for validity.
41 .It Fl c Pa config
42 Specify an alternative configuration file.
43 By default
44 .Pa $HOME/.telescope/config
45 is loaded.
46 .El
47 .Sh TOFU
48 .Nm
49 aims to use the "Trust, but Verify (where appropriate)" approach.
50 The idea is to define three level of verification for a certificate:
51 .Bl -tag -width 12m
52 .It untrusted
53 the server fingerprint does NOT match the stored value
54 .It trusted
55 the server fingerprint matches the store one
56 .It verified
57 the fingerprint matches and has been verified out-of-band
58 .El
59 .Pp
60 Most of the time the
61 .Dq trusted
62 level is enough, but where is appropriate users should be able to
63 verify out-of-band the certificate.
64 .Pp
65 At the moment, there is no built-in support for an out-of-band
66 verification though.
67 .Pp
68 Known certificates are store in
69 .Pa ~/.telescope/known_hosts
70 with a format similar to the
71 .Xr ssh 1 Ns '
72 .Pa known_hosts
73 file.
74 Each line is a record and it's made up by three fields, separated by a
75 single space, according to the following format:
76 .Dq HOST HASH TRUSTED
77 where:
78 .Bl -tag -width 12m
79 .It HOST
80 the hostname, optionally followed by a colon (":") and a port number.
81 .It HASH
82 is the hash of the certificate, as outputted by
83 .Xr tls_peer_cert_hash 3 .
84 .It TRUSTED
85 a single digit.
86 0 means trusted, 1 verified.
87 .El
88 .Sh DEFAULT KEY BINDINGS
89 The default key bindings are very similar to GNU Emacs, but care has
90 been taken to include also bindings familiar for
91 .Xr vi 1
92 and
93 .Dq CUA
94 users.
95 In the following examples, C-x means Control-x, M-x means Meta-x,
96 where the Meta key may be either a special key on the keyboard or the
97 ALT key; otherwise ESC followed by the key X works as well, and C-M-x
98 means to press the key X together with both Control and Meta.
99 .Pp
100 Keys are usually a single character, like
101 .Sq p
102 or
103 .Sq n ,
104 but some special keys are accepted as well.
105 .Pp
106 .Bl -tag -width 16m -offset indent -compact
107 .It <up>
108 Up arrow
109 .It <down>
110 Down arrow
111 .It <left>
112 Left arrow
113 .It <right>
114 Right arrow
115 .It <prior>
116 Previous page/Page up
117 .It <next>
118 Next page/Page down
119 .It <home>
120 Home
121 .It <end>
122 End
123 .It <f0> thru <f63>
124 Function keys
125 .It del or backspace
126 Backspace
127 .It esc
128 Escape
129 .It space or spc
130 Space
131 .It enter or ret
132 Enter
133 .It tab
134 Tab
135 .It backtab
136 Depends on the configuration of the terminal emulator.
137 Usually is shift tab though.
138 .El
139 .Ss GNU Emacs-like keys
140 .Bl -tag -width xxxxxxxxxxxx -offset indent -compact
141 .It C-p
142 previous-line
143 .It C-n
144 next-line
145 .It C-f
146 forward-char
147 .It C-b
148 backward-char
149 .It M-{
150 backward-paragraph
151 .It M-}
152 forward-paragraph
153 .It C-a
154 move-beginning-of-line
155 .It C-e
156 move-end-of-line
157 .It M-v, M-space
158 scroll-up
159 .It C-v, space
160 scroll-down
161 .It M-<
162 beginning-of-buffer
163 .It M->
164 end-of-buffer
165 .It C-x C-c
166 kill-telescope
167 .It C-g
168 clear-minibuf
169 .It M-x
170 execute-extended-command
171 .It C-c {
172 dec-fill-column
173 .It C-c }
174 inc-fill-column
175 .It C-c p
176 previous-heading
177 .It C-c n
178 next-heading
179 .It >
180 load-url
181 .It <
182 load-current-url
183 .It C-x C-f
184 load-url
185 .It C-x M-f
186 load-current-url
187 .It C-x t 0
188 tab-close
189 .It C-x t 1
190 tab-close-other
191 .It C-x t 2
192 tab-new
193 .It C-x t o
194 tab-next
195 .It C-x t O
196 tab-previous
197 .It C-x t m
198 tab-move
199 .It C-x t M
200 tab-move-to
201 .It B, C-M-b
202 previous-page
203 .It F, C-M-f
204 next-page
205 .It <f7> a
206 bookmark-page
207 .It <f7> <f7>
208 list-bookmarks
209 .El
210 .Ss Xr vi 1 Ns -like keys
211 .Bl -tag -width xxxxxxxxxxxx -offset indent -compact
212 .It k
213 previous-line
214 .It j
215 next-line
216 .It l
217 forward-char
218 .It h
219 backward-char
220 .It {
221 backward-paragraph
222 .It }
223 forward-paragraph
224 .It ^
225 move-beginning-of-line
226 .It $
227 move-end-of-line
228 .It K
229 scroll-line-up
230 .It J
231 scroll-line-down
232 .It g g
233 beginning-of-buffer
234 .It G
235 end-of-buffer
236 .It g D
237 tab-close
238 .It g N
239 tab-new
240 .It g t
241 tab-next
242 .It g T
243 tab-previous
244 .It g M-t
245 tab-move
246 .It g M-T
247 tab-move-to
248 .It H
249 previous-page
250 .It L
251 next-page
252 .It q
253 kill-telescope
254 .It ESC
255 clear-minibuf
256 .It :
257 execute-extended-command
258 .El
259 .Ss CUA-like keys
260 .Bl -tag -width xxxxxxxxxxxx -offset indent -compact
261 .It <up>
262 previous-line
263 .It <down>
264 next-line
265 .It <right>
266 forward-char
267 .It <left>
268 backward-char
269 .It <prior>
270 scroll-up
271 .It <next>
272 scroll-down
273 .It C-w
274 tab-close
275 .It C-t
276 tab-new
277 .It M-<prior>
278 tab-previous
279 .It M-<next>
280 tab-next
281 .It M-<left>
282 previous-page
283 .It M-<right>
284 next-page
285 .It <f5>
286 reload-page
287 .It r
288 reload-page
289 .El
290 .Ss Neither Emacs nor vi specific
291 .Bl -tag -width xxxxxxxxxxxx -offset indent -compact
292 .It <f1>
293 toggle-help
294 .It enter
295 push-button
296 .It M-enter
297 push-button-new-tab
298 .It M-tab
299 previous-button
300 .It backtab
301 previous-button
302 .It tab
303 next-button
304 .It M-t
305 tab-select
306 .It M-L
307 link-select
308 .It M-/
309 swiper
310 .El
311 .Ss Minibuffer-specific keys
312 .Bl -tag -width xxxxxxxxxxxx -offset indent -compact
313 .It enter
314 mini-complete-and-exit
315 .It C-g
316 mini-abort
317 .It ESC
318 mini-abort
319 .It C-d
320 mini-delete-char
321 .It del
322 mini-delete-backward-char
323 .It backspace
324 mini-delete-backward-char
325 .It C-h
326 mini-delete-backward-char
327 .It C-b
328 backward-char
329 .It C-f
330 forward-char
331 .It <left>
332 backward-char
333 .It <right>
334 forward-char
335 .It C-e
336 move-end-of-line
337 .It C-a
338 move-beginning-of-line
339 .It <end>
340 move-end-of-line
341 .It <home>
342 move-beginning-of-line
343 .It C-k
344 mini-kill-line
345 .It M-p
346 mini-previous-history-element
347 .It M-n
348 mini-next-history-element
349 .It C-p
350 previous-completion
351 .It C-n
352 next-completion
353 .It <up>
354 previous-completion
355 .It <down>
356 next-completion
357 .It tab
358 insert-current-candidate
359 .El
360 .Sh INTERACTIVE COMMANDS
361 Follows the documentation for the interactive commands.
362 These commands can be bound to a key or executed with
363 .Ic execute-extended-command .
364 .Ss Movement commands
365 .Bl -tag -width execute-extended-command -compact
366 .It Ic backward-char
367 Move point one character backward.
368 .It Ic backward-paragraph
369 Move point one paragraph backward.
370 .It Ic beginning-of-buffer
371 Move point to the beginning of the buffer.
372 .It Ic end-of-buffer
373 Move point to the end of the buffer.
374 .It Ic forward-char
375 Move point one character forward.
376 .It Ic forward-paragraph
377 Move point one paragraph forward.
378 .It Ic insert-current-candidate
379 Copy the current selection text as minibuffer input.
380 .It Ic move-beginning-of-line
381 Move point at the beginning of the current (visual) line.
382 .It Ic move-end-of-line
383 Move point at the end of the current (visual) line.
384 .It Ic next-button
385 Move point to the next link.
386 .It Ic next-completion
387 Select the next completion.
388 .It Ic next-heading
389 Move point to the next heading.
390 .It Ic next-line
391 Move point to the next (visual) line, in the same column if possible.
392 .It Ic previous-button
393 Move point to the previous link.
394 .It Ic previous-completion
395 Select the previous completion.
396 .It Ic previous-heading
397 Move point to the previous heading.
398 .It Ic previous-line
399 Move point to the previous (visual) line.
400 .El
401 .Ss Bookmark-related commands
402 .Bl -tag -width execute-extended-command -compact
403 .It Ic bookmark-page
404 Add a link to the bookmark file.
405 It preloads the minibuffer with the current URL.
406 .It Ic list-bookmarks
407 Load the bookmarks page.
408 .El
409 .Ss Tab-related commands
410 .Bl -tag -width execute-extended-command -compact
411 .It Ic tab-close
412 Close the current tab.
413 .It Ic tab-close-other
414 Close all tabs but the current one.
415 .It Ic tab-move
416 Move the current tab after the next one, wrapping around if
417 needed.
418 .It Ic tab-move-to
419 Move the current tab before the previous one, wrapping around if needed.
420 .It Ic tab-new
421 Open a new tab.
422 .It Ic tab-next
423 Focus next tab, wrapping around eventually.
424 .It Ic tab-previous
425 Focus the previous tab, wrapping around eventually.
426 .It Ic tab-select
427 Switch to a tab using the minibuffer.
428 .El
429 .Ss Misc commands
430 .Bl -tag -width execute-extended-command -compact
431 .It Ic clear-minibuf
432 Clears the echo area.
433 .It Ic dec-fill-column
434 Decrements fill-column by two.
435 .It Ic execute-extended-command
436 Prompts for a command name using the minibuffer.
437 .It Ic kill-telescope
438 Quit
439 .Nm .
440 .It Ic inc-fill-column
441 Increments fill-column by two.
442 .It Ic link-select
443 Select and visit a link using the minibuffer.
444 .It Ic load-current-url
445 Prompts for an URL, the minibuffer is preloaded with the current
446 one.
447 .It Ic load-url
448 Prompts for an URL.
449 .It Ic next-page
450 Load the next item in the history list.
451 .It Ic olivetti-mode
452 Toggle olivetti mode (i.e. horizontal centering of the lines of the
453 window.)
454 .It Ic previous-page
455 Load the previous item in the history list.
456 .It Ic push-button
457 Follow the link on the current line, or toggle the visibility of the
458 following preformatted block if called when the cursor is on the
459 heading of the block.
460 .It Ic push-button-new-tab
461 Follow the link on the current line on a new tab.
462 .It Ic redraw
463 Redraw the screen, useful if some background program messed up the
464 display.
465 .It Ic reload-page
466 Reload the current page.
467 .It Ic scroll-down
468 Scroll down by one visual page.
469 .It Ic scroll-line-down
470 Scroll down by one line.
471 .It Ic scroll-line-up
472 Scroll up by one line.
473 .It Ic scroll-up
474 Scroll up by one visual page.
475 .It Ic swiper
476 Jump to a line using the minibuffer.
477 .It Ic toggle-help
478 Toggle side window with help about available keys and their associated
479 interactive command.
480 .El
481 .Ss Minibuffer commands
482 .Bl -tag -width execute-extended-command -compact
483 .It Ic mini-abort
484 Abort the current minibuffer action.
485 .It Ic mini-complete-and-exit
486 Complete the current minibuffer action.
487 .It Ic mini-delete-backward-char
488 Delete the character before the point.
489 .It Ic mini-delete-char
490 Delete the character after the point.
491 .It Ic mini-kill-line
492 Delete from the point until the end of the line.
493 .It Ic mini-next-history-element
494 Load the previous history element.
495 .It Ic mini-previous-history-element
496 Load the next history element.
497 .El
498 .Ss Aliases
499 The following aliases are available during
500 .Ic execute-extended-command :
501 .Bl -tag -width 16m -compact
502 .It Ic tabn
503 .Ic tab-next
504 .It Ic tabnew
505 .Ic tab-new
506 .It Ic tabp
507 .Ic tab-previous
508 .It Ic q No and Ic wq
509 .Ic kill-telescope
510 .El
511 .Sh CONFIGURATION FILE
512 During the startup,
513 .Nm
514 reads the configuration file at
515 .Pa ~/.telescope/config
516 or the one given with the
517 .Fl c
518 flag.
519 .Pp
520 The format of the configuration file is fairly flexible.
521 The current line can be extended over multiple ones using a
522 backslash
523 .Pq Sq \e .
524 Comments can be put anywhere in the file using a hash mark
525 .Pq Sq # ,
526 and extend to the end of the current line, but backslashes can't be
527 used to extend comments over multiple lines.
528 .Pp
529 The following constructs are available:
530 .Bl -tag -width Ds
531 .It Ic bind Ar map Ar key Ar cmd
532 Bind
533 .Ar key
534 to the function
535 .Ar cmd
536 in the keymap
537 .Ar map .
538 Valid values for map are
539 .Dq global-map
540 .Pq i.e. when the user is viewing a page
541 and
542 .Dq minibuffer-map
543 .Pq i.e. when the minibuffer has the focus.
544 .Ar key
545 follows the same syntax described in
546 .Sx DEFAULT KEY BINDINGS
547 and all the possible functions are listed in
548 .Sx INTERACTIVE COMMANDS .
549 .It Ic proxy Ar proto Ic via Ar url
550 Use
551 .Ar url
552 as proxy for all URLs with
553 protocol
554 .Ar proto .
555 .Ar url
556 must be a Gemini URI without path, query and fragment component.
557 .It Ic set Ar opt No = Ar val
558 Set the option
559 .Ar opt
560 to the value
561 .Ar val .
562 Valid options are:
563 .Pp
564 .Bl -tag -width twelveletters -compact
565 .It enable-colors
566 .Pq integer
567 If not zero, enable colours.
568 By default is 1 if
569 .Ev NO_COLORS
570 is not set, 0 otherwise.
571 .It fill-column
572 .Pq integer
573 If greater than zero, lines of text will be formatted in a way that
574 don't exceed the given number of columns.
575 By default is 80.
576 .It hide-pre-blocks
577 .Pq integer
578 If nonzero, hide by default the body of the preformatted blocks.
579 By default is zero.
580 .Ic push-button
581 can be used to toggle the visibility per-block.
582 .It hide-pre-context
583 .Pq integer
584 If nonzero, hide the start and end line of the preformatted blocks.
585 If both hide-pre-context and hide-pre-blocks are nonzero, preformatted
586 blocks are irremediably hidden.
587 By default is zero.
588 .It new-tab-url
589 .Pq string
590 URL for the new tab page.
591 By default is
592 .Dq about:new .
593 .It olivetti-mode
594 .Pq integer
595 Enable
596 .Ic olivetti-mode
597 if non zero.
598 By default is 1.
599 .El
600 .It Ic style Ar name Ar option
601 Change the styling of the element identified by
602 .Ar name .
603 Multiple options may be specified within curly braces.
604 Valid style identifiers are:
605 .Bl -tag -width 16m -compact -offset Ds
606 .It line
607 for the area outside the lines in the body of the page.
608 .It line.compl
609 for the completion in the minibuffer
610 .It line.compl.current
611 for the current completion
612 .It line.text
613 for text lines.
614 .It line.link
615 for link lines.
616 .It line.title1..3
617 for headings
618 .It line.item
619 for item lines.
620 .It line.quote
621 for quotes.
622 .It line.pre.start
623 for the heading of a preformatted block.
624 .It line.pre
625 for the content of a preformatted block.
626 .It line.pre.end
627 for the closing line of a preformatted block.
628 .It minibuffer
629 for the minibuffer
630 .Dq i.e. the last line of the window
631 .It modeline
632 for the modeline
633 .Dq i.e. the info line right above the minibuffer
634 .It tabline
635 for the tabline.
636 .It tabline.tab
637 for the non-focused tabs.
638 .It tabline.current
639 for the focused tab.
640 .El
641 .Pp
642 Valid options are:
643 .Bl -tag -width Ds
644 .It Ic attr Ar prefix Oo Ar line Oo Ar trail Oc Oc
645 Sets the text attributes.
646 If only one value is given,
647 .Ar line
648 and
649 .Ar trail
650 default to that; if two values are given then
651 .Ar trail
652 defaults to
653 .Ar prefix .
654 Each attribute is a comma-separated list of keywords:
655 .Bl -tag -width underline -compact -offset Ds
656 .It Ic normal
657 no attributes.
658 .It Ic standout
659 best highlighting mode for the terminal.
660 .It Ic underline
661 underlines the text.
662 .It Ic reverse
663 reverses background/foreground colors.
664 .It Ic blink
665 makes the text blinking.
666 .It Ic dim
667 half bright.
668 .It Ic bold
669 extra bright or bold.
670 .El
671 .Pp
672 Only the styles under the
673 .Dq line.
674 prefix accept up to three attributes.
675 The other will only use the first one given.
676 .It Ic bg Ar prefix Oo Ar line Oo Ar trail Oc Oc
677 Sets the background color.
678 Follows the same behaviour as
679 .Ic attr
680 regarding the optional parameters.
681 The colour is one of black, red, green, yellow, blue,
682 magenta, cyan and white; colour0 to colour255
683 .Pq or color0 to color255
684 from the 256-colour set;
685 default for the default colour.
686 .It Ic fg Ar prefix Oo Ar line Oo Ar trail Oc Oc
687 Sets the foreground color.
688 It behaves just like
689 .Ic bg .
690 .It Ic prefix Ar prfx Op Ar cont
691 Sets the prefix for the current line type to
692 .Ar prfx
693 and
694 .Ar cont
695 as the prefix for the continuation lines
696 .Pq i.e. when a long line gets wrapped.
697 If
698 .Ar cont
699 is not given its value will be the same of
700 .Ar prfx .
701 .El
702 .El
703 .Sh FILES
704 .Bl -tag -width Ds -compact
705 .It Pa ~/.telescope/bookmarks.gmi
706 Holds the bookmarks.
707 .It Pa ~/.telescope/config
708 Default configuration file.
709 .It Pa ~/.telescope/known_hosts
710 Contains a list of host keys for all the hosts the user has visited.
711 See the TOFU section for more info.
712 .It Pa ~/.telescope/session
713 Contains the list of opened tabs in the last session, one per line.
714 Gets written on
715 .Ic kill-telescope
716 and loaded on startup.
717 .El
718 .Sh EXAMPLES
719 The following is my config file:
720 .Bd -literal -offset indent
721 # enable colors regardless of $NO_COLOR
722 set enable-colors = 1
724 style line.item {
725 prefix " • " " "
728 style line.link {
729 prefix "→ " " "
732 style line.quote {
733 prefix " ┃ "
735 .Ed
736 .Pp
737 It's possible to browse
738 .Dq the small web
739 .Pq i.e. simple websites
740 by using programs like the duckling-proxy by defining a proxy in
741 .Pa ~/.telescope/config :
742 .Bd -literal -offset indent
743 proxy http via "gemini://localhost:1965"
744 proxy https via "gemini://localhost:1965"
745 .Ed
746 .Pp
747 To load
748 .Nm
749 without any configuration use
750 .Bd -literal -offset indent
751 telescope -c /dev/null
752 .Ed
753 .Sh AUTHORS
754 .An -nosplit
755 The
756 .Nm
757 program was written by
758 .An Omar Polo Aq Mt op@omarpolo.com .