# 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 this is a very new project and can be considered beta at best.
That said, I am using antigen full time now on my work machine. Also, please
read the commit comments of the changesets when you pull a new version of
antigen.

## Show off

> Enough talk. Let's fight!
>   -- Po, Kung-fu Panda.

You're going to experience antigen right in your open shell. No `.zshrc`
tweaking and reading the rest of this documentation. Kinda like an ice-cream
sample, if you will.

Get and load antigen.

    curl https://raw.github.com/zsh-users/antigen/master/antigen.zsh > antigen.zsh
    source antigen.zsh

There. You now have all the antigen goodies. Let's try install some plugins. How
about some color to start with. Get the [syntax highlighting plugin][] by
running

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

Now let it do its thing and once its done and you're back at your prompt, try
and type a command. See that? Colors!

So, you do git? ruby? git and ruby? There are lots of awesome plugins over at
oh-my-zsh. Treat yourself to some.

    antigen-bundle robbyrussell/oh-my-zsh plugins/ruby
    antigen-bundle robbyrussell/oh-my-zsh plugins/git

There are lots of plugins out there in the wild and people are writing zsh
utilities as small scripts all the time. Antigen is compatible with all of them.
The plugins and scripts don't need any special handling to be compatible with
antigen.

Another example, [kennethreitz's autoenv](autoenv). Just a bundle command away.

    antigen-bundle kennethreitz/autoenv

And boom! you have all the autoenv goodness. Just remember how you used to do
these before antigen, clone it, modify your bashrc to source it, load a new
terminal, all just to test it out. Duh!

The side effect of this is that you can tell antigen to grab just about anything
from anyone's `dotfiles` repo, as long as it is in a directory under any repo on
github.

And themes? How would you like a fancy new prompt for yourself?

    antigen-theme funky

No? Not your taste? There are many themes available to you, check out the
oh-my-zsh's [page on themes][]. (You can currently only install themes from
robbyrussell's, i.e., the canonical oh-my-zsh repo).

Note: Many of those plugins and especially themes, assume you have the core
library of oh-my-zsh loaded. So, if you want to experiment further, issue a

    antigen-lib

and continue until you're tired. At which point you can come back to this page
;)

## Usage

So, now that you're here, I'll assume you are convinced and want antigen running
your shell all the time. Sweet. Let's do it.

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`.

Other keyword-only arguments accepted:

`branch` &mdash; Specify the branch of the git repo to be used for this bundle.
Please note that if you specify two plugins to be loaded from the same git repo,
but different branches, then two separate clones of this repo will be
maintained. This is a small implementation detail and shouldn't influence you in
any way.

### 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` &mdash; 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` &mdash; 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` &mdash; These variables
were used previously but are now removed. Please use `ADOTDIR` instead, as
mentioned above.

## Notes on writing plugins

> *TBD*

## 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
[page on themes]: https://github.com/robbyrussell/oh-my-zsh/wiki/Themes
[syntax highlighting plugin]: https://github.com/zsh-users/zsh-syntax-highlighting
[autoenv]: https://github.com/kennethreitz/autoenv
[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