(ring-elements): Make it return a list of the elements of RING in
[bpt/emacs.git] / man / eshell.texi
1 \input texinfo @c -*-texinfo-*-
2 @c %**start of header
3 @setfilename ../info/eshell
4 @settitle Eshell: The Emacs Shell
5 @synindex vr fn
6 @c %**end of header
7
8 @copying
9 This manual is for Eshell, the Emacs shell.
10
11 Copyright @copyright{} 1999, 2000, 2001, 2002, 2004 Free Software Foundation, Inc.
12
13 @quotation
14 Permission is granted to copy, distribute and/or modify this document
15 under the terms of the GNU Free Documentation License, Version 1.1 or
16 any later version published by the Free Software Foundation; with no
17 Invariant Sections, with the Front-Cover texts being ``A GNU
18 Manual'', and with the Back-Cover Texts as in (a) below. A copy of the
19 license is included in the section entitled ``GNU Free Documentation
20 License'' in the Emacs manual.
21
22 (a) The FSF's Back-Cover Text is: ``You have freedom to copy and modify
23 this GNU Manual, like GNU software. Copies published by the Free
24 Software Foundation raise funds for GNU development.''
25
26 This document is part of a collection distributed under the GNU Free
27 Documentation License. If you want to distribute this document
28 separately from the collection, you can do so by adding a copy of the
29 license to the document, as described in section 6 of the license.
30 @end quotation
31 @end copying
32
33 @dircategory Emacs
34 @direntry
35 * Eshell: (eshell). A command shell implemented in Emacs Lisp.
36 @end direntry
37
38 @setchapternewpage on
39
40 @titlepage
41 @sp 4
42 @c The title is printed in a large font.
43 @center @titlefont{User's Guide}
44 @sp
45 @center @titlefont{to}
46 @sp
47 @center @titlefont{Eshell: The Emacs Shell}
48 @ignore
49 @sp 2
50 @center release 2.4
51 @c -release-
52 @end ignore
53 @sp 3
54 @center John Wiegley
55 @c -date-
56
57 @page
58 @vskip 0pt plus 1filll
59 @insertcopying
60 @end titlepage
61
62 @contents
63
64 @c ================================================================
65 @c The real text starts here
66 @c ================================================================
67
68 @ifnottex
69 @node Top, What is Eshell?, (dir), (dir)
70 @top Eshell
71
72 This manual documents Eshell, a shell-like command interpretor
73 implemented in Emacs Lisp. It invokes no external processes except for
74 those requested by the user. It is intended to be a functional
75 replacement for command shells such as @command{bash}, @command{zsh},
76 @command{rc}, or @command{4dos}; since Emacs itself is capable of
77 handling the sort of tasks accomplished by those tools.
78 @c This manual is updated to release 2.4 of Eshell.
79 @end ifnottex
80
81 @menu
82 * What is Eshell?:: A brief introduction to the Emacs Shell.
83 * Command basics:: The basics of command usage.
84 * Commands::
85 * Arguments::
86 * Input/Output::
87 * Process control::
88 * Extension modules::
89 * Extras and Goodies::
90 * Bugs and ideas:: Known problems, and future ideas.
91 * Concept Index::
92 * Function and Variable Index::
93 * Key Index::
94 @end menu
95
96 @node What is Eshell?
97 @chapter What is Eshell?
98 @cindex what is Eshell?
99 @cindex Eshell, what it is
100
101 Eshell is a @dfn{command shell} written in Emacs Lisp. Everything it
102 does, it uses Emacs' facilities to do. This means that Eshell is as
103 portable as Emacs itself. It also means that cooperation with Lisp code
104 is natural and seamless.
105
106 What is a command shell? To properly understand the role of a shell,
107 it's necessary to visualize what a computer does for you. Basically, a
108 computer is a tool; in order to use that tool, you must tell it what to
109 do---or give it ``commands.'' These commands take many forms, such as
110 clicking with a mouse on certain parts of the screen. But that is only
111 one form of command input.
112
113 By far the most versatile way to express what you want the computer to
114 do is by using an abbreviated language called @dfn{script}. In
115 script, instead of telling the computer, ``list my files, please'',
116 one writes a standard abbreviated command word---@samp{ls}. Typing
117 @samp{ls} in a command shell is a script way of telling the computer
118 to list your files.@footnote{This is comparable to viewing the
119 contents of a folder using a graphical display.}
120
121 The real flexibility of this approach is apparent only when you realize
122 that there are many, many different ways to list files. Perhaps you
123 want them sorted by name, sorted by date, in reverse order, or grouped
124 by type. Most graphical browsers have simple ways to express this. But
125 what about showing only a few files, or only files that meet a certain
126 criteria? In very complex and specific situations, the request becomes
127 too difficult to express using a mouse or pointing device. It is just
128 these kinds of requests that are easily solved using a command shell.
129
130 For example, what if you want to list every Word file on your hard
131 drive, larger than 100 kilobytes in size, and which hasn't been looked
132 at in over six months? That is a good candidate list for deletion, when
133 you go to clean up your hard drive. But have you ever tried asking your
134 computer for such a list? There is no way to do it! At least, not
135 without using a command shell.
136
137 The role of a command shell is to give you more control over what your
138 computer does for you. Not everyone needs this amount of control, and
139 it does come at a cost: Learning the necessary script commands to
140 express what you want done. A complicated query, such as the example
141 above, takes time to learn. But if you find yourself using your
142 computer frequently enough, it is more than worthwhile in the long run.
143 Any tool you use often deserves the time spent learning to master it.
144 @footnote{For the understandably curious, here is what that command
145 looks like: But don't let it fool you; once you know what's going on,
146 it's easier than it looks: @code{ls -lt **/*.doc(Lk+50aM+5)}.}
147
148 @menu
149 * Contributors to Eshell:: People who have helped out!
150 @end menu
151
152 @node Contributors to Eshell
153 @section Contributors to Eshell
154 @cindex contributors
155 @cindex authors
156
157 Contributions to Eshell are welcome. I have limited time to work on
158 this project, but I will gladly add any code you contribute to me to
159 this package.
160
161 The following persons have made contributions to Eshell.
162
163 @itemize @bullet
164 @item
165 Eli Zaretskii made it possible for Eshell to run without requiring
166 asynchronous subprocess support. This is important for MS-DOS, which
167 does not have such support.@refill
168
169 @item
170 Miles Bader contributed many fixes during the port to Emacs 21.@refill
171
172 @item
173 Stefan Monnier fixed the things which bothered him, which of course made
174 things better for all.@refill
175
176 @item
177 Gerd Moellmann also helped to contribute bug fixes during the initial
178 integration with Emacs 21.@refill
179
180 @item
181 Alex Schroeder contributed code for interactively querying the user
182 before overwriting files.@refill
183
184 @item
185 Sudish Joseph helped with some XEmacs compatibility issues.@refill
186 @end itemize
187
188 Apart from these, a lot of people have sent suggestions, ideas,
189 requests, bug reports and encouragement. Thanks a lot! Without you
190 there would be no new releases of Eshell.
191
192 @node Command basics
193 @chapter Basic overview
194
195 A command shell is a means of entering verbally-formed commands. This
196 is really all that it does, and every feature described in this manual
197 is a means to that end. Therefore, it's important to take firm hold on
198 exactly what a command is, and how it fits in the overall picture of
199 things.
200
201 @menu
202 * Commands verbs:: Commands always begin with a verb.
203 * Command arguments:: Some verbs require arguments.
204 @end menu
205
206 @node Commands verbs
207 @section Commands verbs
208
209 Commands are expressed using @dfn{script}, a special shorthand language
210 computers can understand with no trouble. Script is an extremely simple
211 language; oddly enough, this is what makes it look so complicated!
212 Whereas normal languages use a variety of embellishments, the form of a
213 script command is always:
214
215 @example
216 @var{verb} [@var{arguments}]
217 @end example
218
219 The verb expresses what you want your computer to do. There are a fixed
220 number of verbs, although this number is usually quite large. On the
221 author's computer, it reaches almost 1400 in number. But of course,
222 only a handful of these are really necessary.
223
224 Sometimes, the verb is all that's written. A verb is always a single
225 word, usually related to the task it performs. @command{reboot} is a
226 good example. Entering that on GNU/Linux will reboot the
227 computer---assuming you have sufficient privileges.
228
229 Other verbs require more information. These are usually very capable
230 verbs, and must be told specifically what to do. The extra information
231 is given in the form of @dfn{arguments}. For example, the
232 @command{echo} verb prints back whatever arguments you type. It
233 requires these arguments to know what to echo. A proper use of
234 @command{echo} looks like this:
235
236 @example
237 echo This is an example of using echo!
238 @end example
239
240 This script command causes the computer to echo back: ``This is an
241 example of using echo!''
242
243 Although command verbs are always simple words, like @command{reboot} or
244 @command{echo}, arguments may have a wide variety of forms. There are
245 textual arguments, numerical arguments---even Lisp arguments.
246 Distinguishing these different types of arguments requires special
247 typing, for the computer to know exactly what you mean.
248
249 @node Command arguments
250 @section Command arguments
251
252 Eshell recognizes several different kinds of command arguments:
253
254 @enumerate
255 @item Strings (also called textual arguments)
256 @item Numbers (floating point or integer)
257 @item Lisp lists
258 @item Lisp symbols
259 @item Emacs buffers
260 @item Emacs process handles
261 @end enumerate
262
263 Most users need to worry only about the first two. The third, Lisp lists,
264 occur very frequently, but almost always behind the scenes.
265
266 Strings are the most common type of argument, and consist of nearly any
267 character. Special characters---those used by Eshell
268 specifically---must be preceded by a backslash (@samp{\}). When in doubt, it
269 is safe to add backslashes anywhere and everywhere.
270
271 Here is a more complicated @command{echo} example:
272
273 @example
274 echo A\ Multi-word\ Argument\ With\ A\ \$\ dollar
275 @end example
276
277 Beyond this, things get a bit more complicated. While not beyond the
278 reach of someone wishing to learn, it is definitely beyond the scope of
279 this manual to present it all in a simplistic manner. Get comfortable
280 with Eshell as a basic command invocation tool, and learn more about the
281 commands on your system; then come back when it all sits more familiarly
282 on your mind. Have fun!
283
284 @node Commands
285 @chapter Commands
286
287 @menu
288 * Invocation::
289 * Completion::
290 * Aliases::
291 * History::
292 * Scripts::
293 * Built-ins::
294 @end menu
295
296 Essentially, a command shell is all about invoking commands---and
297 everything that entails. So understanding how Eshell invokes commands
298 is the key to comprehending how it all works.
299
300 @node Invocation
301 @section Invocation
302
303 Unlike regular system shells, Eshell never invokes kernel functions
304 directly, such as @code{exec(3)}. Instead, it uses the Lisp functions
305 available in the Emacs Lisp library. It does this by transforming the
306 command you specify into a callable Lisp form.@footnote{To see the Lisp
307 form that will be invoked, type: @samp{eshell-parse-command "echo
308 hello"}}
309
310 This transformation, from the string of text typed at the command
311 prompt, to the ultimate invocation of either a Lisp function or external
312 command, follows these steps:
313
314 @enumerate
315 @item Parse the command string into separate arguments.
316 @item
317 @end enumerate
318
319 @node Completion
320 @section Completion
321
322 @node Aliases
323 @section Aliases
324
325 @node History
326 @section History
327
328 Eshell knows a few built-in variables:
329
330 @table @code
331
332 @item $+
333 @vindex $+
334 This variable always contains the current working directory.
335
336 @item $-
337 @vindex $-
338 This variable always contains the previous working directory (the
339 current working directory from before the last @code{cd} command).
340
341 @end table
342
343 @node Scripts
344 @section Scripts
345
346
347 @node Built-ins
348 @section Built-in commands
349
350 Here is a list of built-in commands that Eshell knows about:
351
352 @table @code
353
354 @item cd
355 @findex cd
356 This command changes the current working directory. Usually, it is
357 invoked as @samp{cd foo} where @file{foo} is the new working
358 directory. But @code{cd} knows about a few special arguments:
359
360 When it receives no argument at all, it changes to the home directory.
361
362 Giving the command @samp{cd -} changes back to the previous working
363 directory (this is the same as @samp{cd $-}).
364
365 The command @samp{cd =} shows the directory stack. Each line is
366 numbered.
367
368 With @samp{cd =foo}, Eshell searches the directory stack for a
369 directory matching the regular expression @samp{foo} and changes to
370 that directory.
371
372 With @samp{cd -42}, you can access the directory stack by number.
373
374 @end table
375
376
377 @node Arguments
378 @chapter Arguments
379
380 @menu
381 * The Parser::
382 * Variables::
383 * Substitution::
384 * Globbing::
385 * Predicates::
386 @end menu
387
388 @node The Parser
389 @section The Parser
390
391 @node Variables
392 @section Variables
393
394 @node Substitution
395 @section Substitution
396
397 @node Globbing
398 @section Globbing
399
400 @node Predicates
401 @section Predicates
402
403
404 @node Input/Output
405 @chapter Input/Output
406
407 @node Process control
408 @chapter Process control
409
410
411 @node Extension modules
412 @chapter Extension modules
413
414 @menu
415 * Writing a module::
416 * Module testing::
417 * Directory handling::
418 * Key rebinding::
419 * Smart scrolling::
420 * Terminal emulation::
421 * Built-in UNIX commands::
422 @end menu
423
424 @node Writing a module
425 @section Writing a module
426
427 @node Module testing
428 @section Module testing
429
430 @node Directory handling
431 @section Directory handling
432
433 @node Key rebinding
434 @section Key rebinding
435
436 @node Smart scrolling
437 @section Smart scrolling
438
439 @node Terminal emulation
440 @section Terminal emulation
441
442 @node Built-in UNIX commands
443 @section Built-in UNIX commands
444
445
446 @node Extras and Goodies
447 @chapter Extras and Goodies
448
449 @node Bugs and ideas
450 @chapter Bugs and ideas
451 @cindex reporting bugs and ideas
452 @cindex bugs, how to report them
453 @cindex author, how to reach
454 @cindex email to the author
455 @cindex FAQ
456 @cindex problems, list of common
457
458 If you find a bug or misfeature, don't hesitate to let me know! Send
459 email to @email{johnw@@gnu.org}. Feature requests should also be sent
460 there. I prefer discussing one thing at a time. If you find several
461 unrelated bugs, please report them separately.
462
463 If you have ideas for improvements, or if you have written some
464 extensions to this package, I would like to hear from you. I hope you
465 find this package useful!
466
467 @menu
468 * Known problems::
469 @end menu
470
471 @node Known problems
472 @section Known problems
473 @cindex known bugs
474 @cindex bugs, known
475
476 Below is complete list of known problems with Eshell version 2.4.1,
477 which is the version included with Emacs 21.1.
478
479 @table @asis
480 @item Documentation incomplete
481
482 @item Differentiate between aliases and functions
483
484 Allow for a bash-compatible syntax, such as:
485
486 @example
487 alias arg=blah
488 function arg () @{ blah $* @}
489 @end example
490
491 @item @samp{for i in 1 2 3 @{ grep -q a b && *echo has it @} | wc -l} outputs result after prompt
492
493 In fact, piping to a process from a looping construct doesn't work in
494 general. If I change the call to @code{eshell-copy-handles} in
495 @code{eshell-rewrite-for-command} to use @code{eshell-protect}, it seems
496 to work, but the output occurs after the prompt is displayed. The whole
497 structured command thing is too complicated at present.
498
499 @item Error with @command{bc} in @code{eshell-test}
500
501 On some XEmacs system, the subprocess interaction test fails
502 inexplicably, although @command{bc} works fine at the command prompt.
503
504 @item Eshell does not delete @file{*Help*} buffers in XEmacs 21.1.8+
505
506 In XEmacs 21.1.8, the @file{*Help*} buffer has been renamed such that
507 multiple instances of the @file{*Help*} buffer can exist.
508
509 @item Pcomplete sometimes gets stuck
510
511 You press @key{TAB}, but no completions appear, even though the
512 directory has matching files. This behavior is rare.
513
514 @item @samp{grep python $<rpm -qa>} doesn't work, but using @samp{*grep} does
515
516 This happens because the @code{grep} Lisp function returns immediately,
517 and then the asynchronous @command{grep} process expects to examine the
518 temporary file, which has since been deleted.
519
520 @item Problem with C-r repeating text
521
522 If the text @emph{before point} reads "./run", and you type @kbd{C-r r u
523 n}, it will repeat the line for every character typed.
524
525 @item Backspace doesn't scroll back after continuing (in smart mode)
526
527 Hitting space during a process invocation, such as @command{make}, will
528 cause it to track the bottom of the output; but backspace no longer
529 scrolls back.
530
531 @item It's not possible to fully @code{unload-feature} Eshell
532
533 @item Menu support was removed, but never put back
534
535 @item Using C-p and C-n with rebind gets into a locked state
536
537 This happened a few times in Emacs 21, but has been unreproducible
538 since.
539
540 @item If an interactive process is currently running, @kbd{M-!} doesn't work
541
542 @item Use a timer instead of @code{sleep-for} when killing child processes
543
544 @item Piping to a Lisp function is not supported
545
546 Make it so that the Lisp command on the right of the pipe is repeatedly
547 called with the input strings as arguments. This will require changing
548 @code{eshell-do-pipeline} to handle non-process targets.
549
550 @item Input redirection is not supported
551
552 See the above entry.
553
554 @item Problem running @command{less} without arguments on Windows
555
556 The result in the Eshell buffer is:
557
558 @example
559 Spawning child process: invalid argument
560 @end example
561
562 Also a new @command{less} buffer was created with nothing in it@dots{}
563 (presumably this holds the output of @command{less}).
564
565 If @command{less.exe} is invoked from the Eshell command line, the
566 expected output is written to the buffer.
567
568 Note that this happens on NT-Emacs 20.6.1 on Windows 2000. The term.el
569 package and the supplied shell both use the @command{cmdproxy} program
570 for running shells.
571
572 @item Implement @samp{-r}, @samp{-n} and @samp{-s} switches for @command{cp}
573
574 @item Make @kbd{M-5 M-x eshell} switch to ``*eshell<5>*'', creating if need be
575
576 @item @samp{mv @var{dir} @var{file}.tar} does not remove directories
577
578 This is because the tar option --remove-files doesn't do so. Should it
579 be Eshell's job?
580
581 @item Bind @code{standard-output} and @code{standard-error}
582
583 This would be so that if a Lisp function calls @code{print}, everything
584 will happen as it should (albeit slowly).
585
586 @item When an extension module fails to load, @samp{cd /} gives a Lisp error
587
588 @item If a globbing pattern returns one match, should it be a list?
589
590 @item Make sure syntax table is correct in Eshell mode
591
592 So that @kbd{M-DEL} acts in a predictable manner, etc.
593
594 @item Allow all Eshell buffers to share the same history and list-dir
595
596 @item There is a problem with script commands that output to @file{/dev/null}
597
598 If a script file, somewhere in the middle, uses @samp{> /dev/null},
599 output from all subsequent commands is swallowed.
600
601 @item Split up parsing of text after @samp{$} in @file{esh-var.el}
602
603 Make it similar to the way that @file{esh-arg.el} is structured.
604 Then add parsing of @samp{$[?\n]}.
605
606 @item After pressing @kbd{M-RET}, redisplay before running the next command
607
608 @item Argument predicates and modifiers should work anywhere in a path
609
610 @example
611 /usr/local/src/editors/vim $ vi **/CVS(/)/Root(.)
612 Invalid regexp: "Unmatched ( or \\("
613 @end example
614
615 With @command{zsh}, the glob above expands to all files named
616 @file{Root} in directories named @file{CVS}.
617
618 @item Typing @samp{echo $@{locate locate@}/bin<TAB>} results in a Lisp error
619
620 Perhaps it should interpolate all permutations, and make that the
621 globbing result, since otherwise hitting return here will result in
622 ``(list of filenames)/bin'', which is never valuable. Thus, one could
623 @command{cat} only C backup files by using @samp{ls $@{identity *.c@}~}.
624 In that case, having an alias command name @command{glob} for
625 @command{identity} would be useful.
626
627 @item Once symbolic mode is supported for @command{umask}, implement @command{chmod} in Lisp
628
629 @item Create @code{eshell-expand-file-name}
630
631 This would use a data table to transform things such as @samp{~+},
632 @samp{...}, etc.
633
634 @item Abstract @file{em-smart.el} into @file{smart-scroll.el}
635
636 It only really needs: to be hooked onto the output filter and the
637 pre-command hook, and to have the input-end and input-start markers.
638 And to know whether the last output group was ``successful.''
639
640 @item Allow for fully persisting the state of Eshell
641
642 This would include: variables, history, buffer, input, dir stack, etc.
643
644 @item Implement D as an argument predicate
645
646 It means that files beginning with a dot should be included in the
647 glob match.
648
649 @item A comma in a predicate list should mean OR
650
651 At the moment, this is not supported.
652
653 @item Error if a glob doesn't expand due to a predicate
654
655 An error should be generated only if @code{eshell-error-if-no-glob} is
656 non-@code{nil}.
657
658 @item @samp{(+ RET SPC TAB} does not cause @code{indent-according-to-mode} to occur
659
660 @item Create @code{eshell-auto-accumulate-list}
661
662 This is a list of commands for which, if the user presses @kbd{RET}, the
663 text is staged as the next Eshell command, rather than being sent to the
664 current interactive process.
665
666 @item Display file and line number if an error occurs in a script
667
668 @item @command{wait} doesn't work with process ids at the moment
669
670 @item Enable the direct-to-process input code in @file{em-term.el}
671
672 @item Problem with repeating @samp{echo $@{find /tmp@}}
673
674 With smart display active, if @kbd{RET} is held down, after a while it
675 can't keep up anymore and starts outputting blank lines. It only
676 happens if an asynchronous process is involved@dots{}
677
678 I think the problem is that @code{eshell-send-input} is resetting the
679 input target location, so that if the asynchronous process is not done
680 by the time the next @kbd{RET} is received, the input processor thinks
681 that the input is meant for the process; which, when smart display is
682 enabled, will be the text of the last command line! That is a bug in
683 itself.
684
685 In holding down @kbd{RET} while an asynchronous process is running,
686 there will be a point in between termination of the process, and the
687 running of @code{eshell-post-command-hook}, which would cause
688 @code{eshell-send-input} to call @code{eshell-copy-old-input}, and then
689 process that text as a command to be run after the process. Perhaps
690 there should be a way of killing pending input between the death of the
691 process, and the @code{post-command-hook}.
692
693 @item Allow for a more aggressive smart display mode
694
695 Perhaps toggled by a command, that makes each output block a smart
696 display block.
697
698 @item Create more meta variables
699
700 @table @samp
701 @item $!
702 The reason for the failure of the last disk command, or the text of the
703 last Lisp error.
704
705 @item $=
706 A special associate array, which can take references of the form
707 @samp{$=[REGEXP]}. It indexes into the directory ring.
708 @end table
709
710 @item Eshell scripts can't execute in the background
711
712 @item Support zsh's ``Parameter Expansion'' syntax, i.e. @samp{$@{@var{name}:-@var{val}@}}
713
714 @item Write an @command{info} alias that can take arguments
715
716 So that the user can enter @samp{info chmod}, for example.
717
718 @item Create a mode @code{eshell-browse}
719
720 It would treat the Eshell buffer as a outline. Collapsing the outline
721 hides all of the output text. Collapsing again would show only the
722 first command run in each directory
723
724 @item Allow other revisions of a file to be referenced using @samp{file@{rev@}}
725
726 This would be expanded by @code{eshell-expand-file-name} (see above).
727
728 @item Print ``You have new mail'' when the ``Mail'' icon is turned on
729
730 @item Implement @kbd{M-|} for Eshell
731
732 @item Implement input redirection
733
734 If it's a Lisp function, input redirection implies @command{xargs} (in a
735 way@dots{}). If input redirection is added, also update the
736 @code{file-name-quote-list}, and the delimiter list.
737
738 @item Allow @samp{#<@var{word} @var{arg}>} as a generic syntax
739
740 With the handling of @emph{word} specified by an
741 @code{eshell-special-alist}.
742
743 @item In @code{eshell-veal-using-options}, allow a @code{:complete} tag
744
745 It would be used to provide completion rules for that command. Then the
746 macro will automagically define the completion function.
747
748 @item For @code{eshell-command-on-region}, apply redirections to the result
749
750 So that @samp{+ > 'blah} would cause the result of the @code{+} (using
751 input from the current region) to be inserting into the symbol
752 @code{blah}.
753
754 If an external command is being invoked, the input is sent as standard
755 input, as if a @samp{cat <region> |} had been invoked.
756
757 If a Lisp command, or an alias, is invoked, then if the line has no
758 newline characters, it is divided by whitespace and passed as arguments
759 to the Lisp function. Otherwise, it is divided at the newline
760 characters. Thus, invoking @code{+} on a series of numbers will add
761 them; @code{min} would display the smallest figure, etc.
762
763 @item Write @code{eshell-script-mode} as a minor mode
764
765 It would provide syntax, abbrev, highlighting and indenting support like
766 @code{emacs-lisp-mode} and @code{shell-mode}.
767
768 @item In the history mechanism, finish the @command{bash}-style support
769
770 This means @samp{!n}, @samp{!#}, @samp{!:%}, and @samp{!:1-} as separate
771 from @samp{!:1*}.
772
773 @item Support the -n command line option for @command{history}
774
775 @item Implement @command{fc} in Lisp
776
777 @item Specifying a frame as a redirection target should imply the currently active window's buffer
778
779 @item Implement @samp{>@var{func-or-func-list}}
780
781 This would allow for an ``output translators'', that take a function to
782 modify output with, and a target. Devise a syntax that works well with
783 pipes, and can accommodate multiple functions (i.e., @samp{>'(upcase
784 regexp-quote)} or @samp{>'upcase}).
785
786 @item Allow Eshell to read/write to/from standard input and output
787
788 This would be optional, rather than always using the Eshell buffer.
789 This would allow it to be run from the command line (perhaps).
790
791 @item Write a @command{help} command
792
793 It would call subcommands with @option{--help}, or @option{-h} or
794 @option{/?}, as appropriate.
795
796 @item Implement @command{stty} in Lisp
797
798 @item Support @command{rc}'s matching operator, e.g. @samp{~ (@var{list}) @var{regexp}}
799
800 @item Implement @command{bg} and @command{fg} as editors of @code{eshell-process-list}
801
802 Using @command{bg} on a process that is already in the background does
803 nothing. Specifying redirection targets replaces (or adds) to the list
804 current being used.
805
806 @item Have @command{jobs} print only the processes for the current shell
807
808 @item How can Eshell learn if a background process has requested input?
809
810 @item Support @samp{2>&1} and @samp{>&} and @samp{2>} and @samp{|&}
811
812 The syntax table for parsing these should be customizable, such that the
813 user could change it to use rc syntax: @samp{>[2=1]}.
814
815 @item Allow @samp{$_[-1]}, which would indicate the last element of the array
816
817 @item Make @samp{$x[*]} equal to listing out the full contents of @samp{x}
818
819 Return them as a list, so that @samp{$_[*]} is all the arguments of the
820 last command.
821
822 @item Copy ANSI code handling from @file{term.el} into @file{em-term.el}
823
824 Make it possible for the user to send char-by-char to the underlying
825 process. Ultimately, I should be able to move away from using term.el
826 altogether, since everything but the ANSI code handling is already part
827 of Eshell. Then, things would work correctly on MS-Windows as well
828 (which doesn't have @file{/bin/sh}, although @file{term.el} tries to use
829 it).
830
831 @item Make the shell spawning commands be visual
832
833 That is, make (@command{su}, @command{bash}, @command{telnet},
834 @command{rlogin}, @command{rsh}, etc.) be part of
835 @code{eshell-visual-commands}. The only exception is if the shell is
836 being used to invoke a single command. Then, the behavior should be
837 based on what that command is.
838
839 @item Create a smart viewing command named @command{open}
840
841 This would search for some way to open its argument (similar to opening
842 a file in the Windows Explorer).
843
844 @item Alias @command{read} to be the same as @command{open}, only read-only
845
846 @item Write a @command{tail} command which uses @code{view-file}
847
848 It would move point to the end of the buffer, and then turns on
849 auto-revert mode in that buffer at frequent intervals---and a
850 @command{head} alias which assums an upper limit of
851 @code{eshell-maximum-line-length} characters per line.
852
853 @item Make @command{dgrep} load @code{dired}, mark everything, then invoke @code{dired-do-search}
854
855 @item Write mesh.c
856
857 This would run Emacs with the appropriate arguments to invoke Eshell
858 only. That way, it could be listed as a login shell.
859
860 @item Use an intangible @code{PS2} string for multi-line input prompts
861
862 @item Auto-detect when a command is visual, by checking @code{TERMCAP} usage
863
864 @item The first keypress after @kbd{M-x watson} triggers `eshell-send-input'
865
866 @item Make @kbd{/} electric
867
868 So that it automatically expands and corrects pathnames. Or make
869 pathname completion for Pcomplete auto-expand @samp{/u/i/std<TAB>} to
870 @samp{/usr/include/std<TAB>}.
871
872 @item Write the @command{pushd} stack to disk along with @code{last-dir-ring}
873
874 @item Add options to @code{eshell/cat} which would allow it to sort and uniq
875
876 @item Implement @command{wc} in Lisp
877
878 Add support for counting sentences, paragraphs, pages, etc.
879
880 @item Once piping is added, implement @command{sort} and @command{uniq} in Lisp
881
882 @item Implement @command{touch} in Lisp
883
884 @item Implement @command{comm} in Lisp
885
886 @item Implement an @command{epatch} command in Lisp
887
888 This would call @code{ediff-patch-file}, or @code{ediff-patch-buffer},
889 depending on its argument.
890
891 @item Have an option such that @samp{ls -l} generates a dired buffer
892
893 @item Write a version of @command{xargs} based on command rewriting
894
895 That is, @samp{find X | xargs Y} would be indicated using @samp{Y
896 $@{find X@}}. Maybe @code{eshell-do-pipelines} could be changed to
897 perform this on-thy-fly rewriting.
898
899 @item Write an alias for @command{less} that brings up a @code{view-mode} buffer
900
901 Such that the user can press @key{SPC} and @key{DEL}, and then @key{q}
902 to return to Eshell. It would be equivalent to:
903 @samp{X > #<buffer Y>; view-buffer #<buffer Y>}.
904
905 @item Make @code{eshell-mode} as much a full citizen as @code{shell-mode}
906
907 Everywhere in Emacs where @code{shell-mode} is specially noticed, add
908 @code{eshell-mode} there.
909
910 @item Permit the umask to be selectively set on a @command{cp} target
911
912 @item Problem using @kbd{M-x eshell} after using @code{eshell-command}
913
914 If the first thing that I do after entering Emacs is to run
915 @code{eshell-command} and invoke @command{ls}, and then use @kbd{M-x
916 eshell}, it doesn't display anything.
917
918 @item @kbd{M-RET} during a long command (using smart display) doesn't work
919
920 Since it keeps the cursor up where the command was invoked.
921
922 @end table
923
924 @node Concept Index
925 @unnumbered Concept Index
926
927 @printindex cp
928
929 @node Function and Variable Index
930 @unnumbered Function and Variable Index
931
932 @printindex fn
933
934 @node Key Index
935 @unnumbered Key Index
936
937 @printindex ky
938 @bye
939
940 @ignore
941 arch-tag: 776409ba-cb15-42b9-b2b6-d2bdc7ebad01
942 @end ignore