# Antigen
  
  Antigen is a small set of functions that help you easily manage your shell (zsh)
  plugins, called bundles. The concept is pretty much the same as bundles in a
  typical vim+pathogen setup. Antigen is to zsh, what [Vundle][] is to vim.

  **Please** note that antigen is currently is alpha stage and will have backwards
  incompatible changes now and then, until we have a pretty stable system we can
  reason about. **Please** read the commit comments of the changesets when you
  pull a new version of antigen.

  # Quick Usage

  First, clone this repo, probably as a submodule if you have your dotfiles in a
  git repo,
  
      git clone https://github.com/sharat87/antigen.git

  The usage should be very familiar to you if you use Vundle. A typical `.zshrc`
  might look like this

      source /path-to-antigen-clone/antigen.zsh

  
      # Load the oh-my-zsh's library.

      antigen-lib

  
      # Bundles from the default repo (robbyrussell's oh-my-zsh).

      antigen-bundle git
      antigen-bundle heroku
      antigen-bundle pip
      antigen-bundle lein
      antigen-bundle command-not-found

  
      # Syntax highlighting bundle.

      antigen-bundle zsh-users/zsh-syntax-highlighting

  
      # Load the theme.

      antigen-theme robbyrussell

      # Tell antigen that you're done.

      antigen-apply

  Open your zsh with this zshrc and you should see all the bundles you defined
  here, getting installed. Once its done, you are ready to roll. The complete

  syntax for the `antigen-bundle` command is discussed further down on this page.

  
  # Motivation
  
  If you use zsh and [oh-my-zsh][], you know that having many different plugins
  that are developed by many different authors in a single (sub)repo is not a very
  easy to maintain. There are some really fantastic plugins and utilities in
  oh-my-zsh, but having them all in a single repo doesn't really scale well. And I

  admire robbyrussell's efforts for reviewing and merging the gigantic number of

  pull requests the project gets. It needs a better way of plugin management.
  
  This was discussed on [a][1] [few][2] [issues][3], but it doesn't look like
  there was any progress made. So, I'm trying to start this off with antigen,
  hoping to better this situation. Please note that I'm by no means a zsh or any
  shell script expert (far from it).
  
  [1]: https://github.com/robbyrussell/oh-my-zsh/issues/465
  [2]: https://github.com/robbyrussell/oh-my-zsh/issues/377
  [3]: https://github.com/robbyrussell/oh-my-zsh/issues/1014
  
  Inspired by vundle, antigen can pull oh-my-zsh style plugins from various github
  repositories. You are not limited to use plugins from the oh-my-zsh repository
  only and you don't need to maintain your own fork and pull from upstream every
  now and then.
  
  Antigen also lets you switch the prompt theme with one command, just like that
  
      bundle-theme candy
  
  and your prompt is changed, just for this session of course.
  
  # Commands

  ## antigen-bundle

  This command tells antigen to install (if not already installed) and load the
  given plugin. The simplest usage follows the following syntax.

      antigen-bundle <plugin-name>

  This will install the `plugins/<name>` directory from [robbyrussell's

  oh-my-zsh][oh-my-zsh] (can be changed by setting `ANTIGEN_DEFAULT_REPO_URL`).

  However, the above is just syntax sugar for the extended syntax of the
  `antigen-bundle` command.

      antigen-bundle [<url> [<loc>]]

  
  where `<url>` is the repository url and it defaults to [robbyrussell's

  oh-my-zsh][oh-my-zsh] repo (can be changed by setting `ANTIGEN_DEFAULT_REPO_URL`
  discussed further down). `<loc>` is the path under this repository which has the
  zsh plugin. This is typically the directory that contains a `*.plugin.zsh` file,
  but it could contain a completion file or just many `*.zsh` files to be sourced.
  `<loc>` defaults to `/`, which indicates the repository itself is a plugin.

  
  An example invocation would be

      # The following is the same as `antigen-bundle ant`. But for demonstration
      # purposes, we use the extended syntax here.
      antigen-bundle https://github.com/robbyrussell/oh-my-zsh.git plugins/ant

  This would install the ant plugin from robbyrussell's oh-my-zsh repo. Of course,
  github url's can be shortened.

      antigen-bundle robbyrussell/oh-my-zsh plugins/ant

  And since this repo is the default, even that isn't necessary. But we can't
  specify the `loc` without giving the first argument.

  For this and a few other reasons, `antigen-bundle` also supports a simple
  keyword argument syntax, using which we can rewrite the above as

      antigen-bundle --loc=plugins/ant

  Which picks up the default for the `url` argument, and uses the `loc` given to
  it.

  *Note* that you can mix and match positional and keyword arguments. But you
  can't have positional arguments after keyword arguments.

      antigen-bundle robbyrussell/oh-my-zsh --loc=plugins/ant

  
  And keyword arguments don't care about the order in which the arguments are
  specified. The following is perfectly valid.

      antigen-bundle --loc=plugins/ant --url=robbyrussell/oh-my-zsh

  In addition to the above discussed arguments, `antigen-bundle` also takes a
  `btype` keyword-only argument, that is used internally. You shouldn't be
  concerned with this argument, its only used internally and will probably go away
  in the future.  It indicates whether the bundle is a theme or a simple plugin.

  You can use this `antigen-bundle` command not just from your `.zshrc`, but also
  from your shell environment. This allows you to install plugins on the fly and
  try them out. Of course if you want a bundle to be available every time you open
  a shell, put it in your `.zshrc`.

  ## antigen-bundles
  
  If you have a fair number of bundles, using the `antigen-bundle` command can
  look cumbersome. You can use the `antigen-bundles` command to *bulk* define
  bundles instead of individual calls to `antigen-bundle`.
  
  Usage is pretty straightforward. Just pipe the bundle specifications, just as
  you would give to the `antigen-bundle` command, one per line, into the
  `antigen-bundles` command. The easiest way to do this, is using the heredoc
  syntax.
  
      antigen-bundles <<EOF
      # Guess what to install when running an unknown command.
      command-not-found
  
      # The heroku tool helper plugin.
      heroku
  
      EOF
  
  This is equivalent to
  
      antigen-bundle command-not-found
      antigen-bundle heroku
  
  Of course, as you can see, from the lines piped to `antigen-bundles`, empty
  lines and those starting with a `#` are ignored. The rest are passed to
  `antigen-bundle` without any quoting rules applied. They are actually `eval`-ed
  with the `antigen-bundle` command. See the source if you want to really
  understand how it works. Its a very small function.

  ## antigen-update

  This is something you might not want to put in your `.zshrc`. Instead, run it
  occasionally to update all your plugins. It doesn't take any arguments.

      antigen-update

  Please note that the updates that are downloaded are not immediately available.
  You have to open a new shell to be able to see the changes. This is a limitation
  by design since reloading all the plugins *might* have some nasty side effects
  that may not be immediately apparent. Let's just say it can make your shell act
  real quirky.

  **Please note**: This command is not for updating *antigen* itself. Its for
  updating the bundles you are using with antigen.
  
  ## antigen-list

  Use this command to list out the currently *loaded* plugins. Keep in mind that
  this includes any bundles installed on-the-fly.

  Takes no arguments. Gives out the repo url and the plugin's location under the
  repo.

  ## antigen-cleanup

  Used to clean up the clones of repos which are not used by any plugins. It takes
  no arguments. When this is run, it lists out the repo-clones that are available
  but are not used by any plugin *currently loaded*.

  
  This command currently cannot run in a non-interactive mode. So it won't be very
  pleasant to use it in your `.zshrc`.

  ## antigen-lib

  This is a shortcut to

      antigen-bundle --loc=lib

  
  So, it basically installs the oh-my-zsh's library as a bundle. Please note that
  this assumes that the `ANTIGEN_DEFAULT_REPO_URL` is set to the oh-my-zsh repo or
  a fork of that repo. If you want to specify the `url` too, then you can't use

  the `antigen-lib` short cut. You have to do that directly with the
  `antigen-bundle` command.

  
  This is present only for legacy reasons and *might* (or might not) be removed in
  the future.
  
  Use

      antigen-lib

  in  your `.zshrc`, before any `antigen-bundle` declarations. It takes no
  arguments.

  ## antigen-theme

  
  Used for switching the prompt theme. Invoke it with the name of the theme you
  want to use.

      antigen-theme fox

  
  Currently, themes are pulled from robbyrussell's oh-my-zsh repo, but it will
  support getting themes from other repos as well in the future.

  You can use this command to change your theme on the fly in your shell. Go on,
  try out a few themes in your shell before you set it in your `.zshrc`.

  ## antigen-apply

  
  You have to add this command after defining all bundles you need, in your zshrc.
  The completions defined by your bundles will be loaded at this step.
  
  It is possible to load completions as and when a bundle is specified with the
  bundle command, in which case this command would not be necessary. But loading
  the completions is a time-consuming process and your shell will start noticeably
  slow if you have a good number of bundle specifications.
  
  However, if you're a zsh expert and can suggest a way so that this would not be
  necessary, I am very interested in discussing it. Please open up an issue with
  your details. Thanks.

  # Configuration
  
  The following environment variables can be set to customize the behavior of

  antigen. Make sure you set them *before* source-ing `antigen.zsh`.

  
  `ANTIGEN_DEFAULT_REPO_URL` — This is the default repository url that is
  used for `bundle` commands. The default value is robbyrussell's oh-my-zsh repo,
  but you can set this to the fork url of your own fork.

  `ADOTDIR` — This directory is used to store all the repo clones, your
  bundles, themes, caches and everything else antigen requires to run smoothly.
  Defaults to `$HOME/.antigen`.

  **Note**: `ANTIGEN_REPO_CACHE` & `ANTIGEN_BUNDLE_DIR` — These variables
  were used previously but are now removed. Please use `ADOTDIR` instead, as
  mentioned above.

  
  # Meta

  Project is licensed with the [MIT License][license]. To contribute, just fork,
  make changes and send a pull request. If its a rather long/complicated change,
  please consider opening an [issue][] first so we can discuss it out.

  Any comments/suggestions/feedback welcome. Please join the discussion on the

  [reddit page][] of this project. Also, follow me on twitter,
  [@sharat87](twitter).

  [Vundle]: https://github.com/gmarik/vundle
  [oh-my-zsh]: https://github.com/robbyrussell/oh-my-zsh
  [issue]: https://github.com/sharat87/antigen/issues

  [license]: http://mit.sharats.me

  [reddit page]: http://www.reddit.com/r/commandline/comments/u4f26/antigen_a_plugin_manager_for_zsh_shell/

  [twitter]: http://twitter.com/sharat87