GNU ELPA - multishell

Easily use and navigate multiple shell buffers, including remote shells.
Fundamentally, multishell is the function `multishell-pop-to-shell' -
a la `pop-to-buffer' - plus a keybinding. Together, they enable you to:

* Easily get to the input point from wherever you are in a shell buffer,
  or to any of your shell buffers, from anywhere inside emacs.

* Use universal arguments and name completion to launch a new or choose
  among existing shell buffers, and change which is the current default.

* Easily restart exited shells, or shells from emacs prior sessions.

* Specify an initial path for the shell. By using Emacs tramp syntax you
  can launch a sudo and/or remote shell.

  For example, specifying the following at the multishell buffer name
  prompt will:

  * `#root/sudo:root@localhost:/etc` launch a shell in a buffer named
    "*#root*" with a root shell starting in /etc.

  * `/ssh:example.net:` launch a shell buffer in your homedir on
    example.net.  The buffer will be named "*example.net*".

  * `#ex/ssh:example.net|sudo:root@example.net:/etc` launch a root
    shell starting in /etc on example.net named "*#ex*".

  * `interior/ssh:gateway.corp.com|ssh:interior.corp.com:` via
    gateway.corp.com launch a shell in your homedir on interior.corp.com.
    The buffer will be named "*interior*". You could append a sudo hop,
    and so on.

* Thanks to tramp, file visits initiated in remote shell buffers will
  seamlessly be on the hosts where the shells are running, in the auspices
  of the account being used.

* Manage your list of shells, current and past, as a collection.

* Of course, emacs completion makes it easy to switch to an already
  existing shell buffer, or one in your history roster, by name.

See the `multishell-pop-to-shell' docstring for details.

Customize-group `multishell' to select and activate a keybinding and set
various behaviors. Customize-group `savehist' to preserve buffer
names/paths across emacs restarts.

Please use
[the multishell repository](https://github.com/kenmanheimer/EmacsMultishell)
issue tracker to report problems, suggestions, etc, and see that
repository for a bit more documentation.

Change Log:

* 2022-06-04 1.1.10 Ken Manheimer:
  - Autoload customizations so customized multishell keybinding triggers
    load of the package.
  - Refine multishell features description.
* 2021-08-02 1.1.10 Ken Manheimer:
  - Get basic multishell command-key customization working.
* 2020-10-30 1.1.9 Ken Manheimer:
  - Require cl-lib when compiling for cl-letf macro.
* 2020-10-28 1.1.8 Ken Manheimer:
  - Change back to having multishell-list require multishell,
    rather than the other way around, and remove now unnecessary
    new autoloads.
  - Bump version for ELPA release.
* 2020-10-28 1.1.7 Ken Manheimer:
  - Forward compatibility: 'cl-progv' rather than 'progv', resolves
    multishell-list error in recent emacs versions.
  - Incorporate gnu refinements (thanks!)
* 2016-06-27 1.1.6 Ken Manheimer (unreleased):
  - When starting a remote shell, if cd fails to an inital remote
    directory, try again without the cd.
* 2016-02-11 1.1.5 Ken Manheimer:
  - Rectify multishell list sorting to preserve recentness
  - Increment the actual multishell-version setting, neglected for 1.1.4.
* 2016-02-11 1.1.4 Ken Manheimer:
  - hookup multishell-list as completion help buffer.
    Mouse and keyboard selections from help listing properly exits
    minibuffer.
* 2016-02-09 1.1.3 Ken Manheimer:
  multishell-list:
  - add some handy operations, like cloning new entry from existing
  - add optional behaviors to existing operations for returning to
    stopped shells without restarting them.
  - solidify maintaining focus on current entry
  - fix miscellaneous.
* 2016-01-31 1.1.2 Ken Manheimer:
  - Settle puzzling instability of multishell-all-entries
    - The accumulations was putting items going from more to less active
      categories to be put at the end, not beginning.
    - Also, using history for prompting changes history - implement
      no-record option to avoid this when needed.
  - Implement simple edit-in-place multishell-replace-entry and use in
    multishell-list-edit-entry.
  - Remove now unnecessary multishell-list-revert-buffer-kludge.
  - Rectify byte compiler offenses, and other fixes - thanks to Stefan
    Monnier for pointing out many of the corrections.
  - Avoid directly calling tramp functions unnecessarily.
* 2016-01-30 1.1.1 Ken Manheimer:
  - shake out initial multishell-list glitches:
    - (Offer to) delete shell buffer, if present, when deleting entry.
    - Set recency (numeric rank) as initial sort field
    - Recompute list on most operations that affect the order, and try to
      preserve stability. (Kludgy solution, needs work.)
  - Set version to 1.1.1 - multishell-list addition should have been 1.1.0.
* 2016-01-30 1.0.9 Ken Manheimer:
  - Add multishell-list for managing the collection of current and
    history-registered shells: edit, delete, and switch/pop to entries.
    Easy access by invoking `multishell-pop-to-shell' from in the
    `multishell-pop-to-shell' universal arg prompts.
  - Duplicate existing shell buffer names in completions, for distinction.
  - Add paths to buffers started without one, when multishell history dir
    tracking is enabled.
  - Major code cleanup:
    - Simplify multishell-start-shell-in-buffer, in particular using
      shell function, rather than unnecessarily going underneath it.
    - Establish multishell-name-from-entry as canonical name resolver.
    - Fallback to eval-after-load in emacs versions that lack
      with-eval-after-load (eg, emacs 23).
    - save-match-data, where match-string is used
    - resituate some helpers
* 2016-01-24 1.0.8 Ken Manheimer:
  - Work around the shell/tramp mishandling of remote+sudo+homedir problem!
    The work around is clean and simple, basically using high-level `cd'
    API and not messing with the low-level default-directory setting.
    (Turns out the problem was not in my local config. Good riddance to the
    awkward failure handler!)
  - Clean up code resolving the destination shell, starting to document the
    decision tree in the process. See getting-to-a-shell.md in the
    multishell repository, https://github.com/kenmanheimer/EmacsMultishell
  - There may be some shake-out on resolving the destination shell, but
    this release gets the fundamental functionality soundly in place.
* 2016-01-23 1.0.7 Ken Manheimer:
  - Remove notes about tramp remote+sudo+homedir problem. Apparently it's
    due to something in my local site configuration (happens with -q but
    not -Q).
* 2016-01-22 1.0.6 Ken Manheimer:
  - Add multishell-version function.
  - Tweak commentary/comments/docstrings.
  - Null old multishell-buffer-name-history var, if present.
* 2016-01-16 1.0.5 Ken Manheimer:
  - History now includes paths, when designated.
  - Actively track current directory in history entries that have a path.
    Custom control: multishell-history-entry-tracks-current-directory
  - Offer to remove shell's history entry when buffer is killed.
    (Currently the only UI mechanism to remove history entries.)
  - Fix - prevent duplicate entries for same name but different paths
  - Fix - recognize and respect tramp path syntax to start in home dir
  - Simplify history var name, migrate existing history if any from old name
* 2016-01-04 1.0.4 Ken Manheimer - Released to ELPA
* 2016-01-02 Ken Manheimer - working on this in public, but not yet released.

TODO and Known Issues:

* Add custom shell launch prep actions
  - for, eg, port knocking, interface activations
  - shell commands to execute when shell name or path matches a regexp
  - list of (regexp, which - name, path, or both, command)
* Investigate whether we can recognize and provide for failed hops.
  - Tramp doesn't provide useful reactions for any hop but the first
  - Might be stuff we can do to detect and convey failures?
  - Might be no recourse but to seek tramp changes.
* Try minibuffer field boundary at beginning of tramp path, to see whether
  the field boundary magically enables tramp path completion.