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vcsh - manage config files in $HOME via fake bare git repositories

# Index #

1. Contact
2. Introduction
3. Overview
4. Getting Started
5. Usage

# 1 Contact #

There are several ways to get in touch with the author and a small but committed
community around the general idea of version controlling your (digital) life.

* IRC: #vcs-home on irc.oftc.net

* Mailing list: [http://lists.madduck.net/listinfo/vcs-home][vcs-home-list]

* Pull requests or issues on [https://github.com/RichiH/vcsh][vcsh]

# 2 Introduction #

[vcsh][vcsh] allows you to maintain several git repositories in one single
directory. They all maintain their working trees without clobbering each other
or interfering otherwise. By default, all git repositories maintained via
`vcsh` are stored in `$HOME` but you can override this setting if you want to.
All that means that you can have one repository per application or application
family, i.e. `zsh`, `vim`, `ssh`, etc. This, in turn, allows you to clone
custom sets of configurations onto different machines or even for different
users; picking and mixing which configurations you want to use where.
For example, you may not need to have your `mplayer` configuration on a server
or available to root and you may want to maintain different configuration for
`ssh` on your personal and your work machines.

`vcsh` was designed with [mr][mr] in mind so you might want to install that, as
well.

Read `INSTALL.md` and `PACKAGING` for instructions specific to your operating
system.

The following overview will try to give you an idea of the use cases and
advantages of `vcsh`. See sections 3 and 4 for detailed instructions and
examples.

## 2.1 Talks ##

Some people found it useful to look at slides and videos explaining how `vcsh`
works.
They can all be found [on the author's talk page][talks].

# 3 Overview

## 3.1 Comparison to Other Solutions ##

Most people who decide to put their dotfiles under version control start with a
**single repository in $HOME**, adding all their dotfiles (and possibly more)
to it. This works, of course, but can become a nuisance as soon as you try to
manage more than one host.

The next logical step is to create single-purpose repositories in, for example,
~/.dotfiles and to create **symbolic links in $HOME**. This gives you the
flexibility to check out only certain repositories on different hosts. The
downsides of this approach are the necessary manual steps of cloning and
symlinking the individual repositories. It will probably become a nuisance when
you try to manage more than two hosts.

**vcsh** takes this second approach one step further. It expects
**single-purpose repositories** and stores them in a hidden directory (similar
to ~/.dotfiles). However, it does not create symbolic links in $HOME; it puts
the **actual files right into $HOME**.

Furthermore, by making use of [mr] [1], it makes it very easy to enable/disable
and clone a large number of repositories. The use of mr is technically optional
(see 4.3), but it will be an integral part of the proposed system that follows.

## 3.2 Default Directory Layout ##

To illustrate, this is what a possible directory structure looks like.

    $HOME
        |-- $XDG_CONFIG_HOME (defaults to $HOME/.config)
        |   |-- mr
        |   |   |-- available.d
        |   |   |   |-- zsh.vcsh
        |   |   |   |-- gitconfigs.vcsh
        |   |   |   |-- lftp.vcsh
        |   |   |   |-- offlineimap.vcsh
        |   |   |   |-- s3cmd.vcsh
        |   |   |   |-- tmux.vcsh
        |   |   |   |-- vim.vcsh
        |   |   |   |-- vimperator.vcsh
        |   |   |   `-- snippets.git
        |   |   `-- config.d
        |   |       |-- zsh.vcsh        -> ../available.d/zsh.vcsh
        |   |       |-- gitconfigs.vcsh -> ../available.d/gitconfigs.vcsh
        |   |       |-- tmux.vcsh       -> ../available.d/tmux.vcsh
        |   |       `-- vim.vcsh        -> ../available.d/vim.vcsh
        |   `-- vcsh
        |       |-- config
        |       `-- repo.d
        |           |-- zsh.git  -----------+
        |           |-- gitconfigs.git      |
        |           |-- tmux.git            |
        |           `-- vim.git             |
        |-- [...]                           |
        |-- .zshrc   <----------------------+
        |-- .gitignore.d
        |   `-- zsh
        |-- .mrconfig
        `-- .mrtrust

### available.d ###

The files you see in $XDG\_CONFIG\_HOME/mr/available.d are mr configuration files
that contain the commands to manage (checkout, update etc.) a single
repository. vcsh repo configs end in .vcsh, git configs end in .git, etc. This
is optional and your preference. For example, this is what a zsh.vcsh
with read-only access to my zshrc repo looks likes. I.e. in this specific
example, push can not work as you will be using the author's repository. This
is for demonstration, only. Of course, you are more than welcome to clone from
this repository and fork your own.

    [$XDG_CONFIG_HOME/vcsh/repo.d/zsh.git]
    checkout = vcsh clone 'git://github.com/RichiH/zshrc.git' zsh
    update   = vcsh run zsh git pull
    push     = vcsh run zsh git push
    status   = vcsh run zsh git status
    gc       = vcsh run zsh git gc

### config.d ###

$XDG\_CONFIG\_HOME/mr/available.d contains *all available* repositories. Only
files/links present in mr/config.d, however, will be used by mr. That means
that in this example, only the zsh, gitconfigs, tmux and vim repositories will
be checked out. A simple `mr update` run in $HOME will clone or update those
four repositories listed in config.d.

### ~/.mrconfig ###

Finally, ~/.mrconfig will tie together all those single files which will allow
you to conveniently run `mr up` etc. to manage all repositories. It looks like
this:

    [DEFAULT]
    jobs = 5
    # Use if your mr does not have vcsh support in mainline, yet
    include = cat /usr/share/mr/vcsh
    include = cat ${XDG_CONFIG_HOME:-$HOME/.config}/mr/config.d/*

### repo.d ###

$XDG\_CONFIG\_HOME/vcsh/repo.d is the directory where all git repositories which
are under vcsh's control are located. Since their working trees are configured
to be in $HOME, the files contained in those repositories will be put in $HOME
directly.
Of course, [mr] [1] will work with this layout if configured according to this
document (see above).

vcsh will check if any file it would want to create exists. If it exists, vcsh
will throw a warning and exit. Move away your old config and try again.
Optionally, merge your local and your global configs afterwards and push with
`vcsh run foo git push`.

## 3.3 Moving into a New Host ##

To illustrate further, the following steps could move your desired
configuration to a new host.

1. Clone the mr repository (containing available.d, config.d etc.); for
   example: `vcsh clone git://github.com/RichiH/vcsh_mr_template.git mr`
2. Choose your repositories by linking them in config.d (or go with the default
   you may have already configured by adding symlinks to git).
3. Make sure the line 'include = cat /usr/share/mr/vcsh' in .mrconfig points
   to an existing file
4. Run mr to clone the repositories: `cd; mr update`.
5. Done.

Hopefully the above could help explain how this approach saves time by

1. making it easy to manage, clone and update a large number of repositories
   (thanks to mr) and
2. making it unnecessary to create symbolic links in $HOME (thanks to vcsh).

If you want to give vcsh a try, follow the instructions below.

# 4 Getting Started #

Below, you will find a few different methods for setting up vcsh:

1. The Template Way
2. The Steal-from-Template Way
3. The Manual Way

### 4.1 The Template Way ###

#### 4.1.1 Prerequisites ####

Make sure none of the following files and directories exist for your test
(user). If they do, move them away for now:

* ~/.gitignore.d
* ~/.mrconfig
* $XDG\_CONFIG\_HOME/mr/available.d/mr.vcsh
* $XDG\_CONFIG\_HOME/mr/available.d/zsh.vcsh
* $XDG\_CONFIG\_HOME/mr/config.d/mr.vcsh
* $XDG\_CONFIG\_HOME/vcsh/repo.d/mr.git/

All of the files are part of the template repository, the directory is where
the template will be stored.

    apt-get install mr

#### 4.1.2 Install vcsh ####

#### 4.1.2.1 Debian ####

If you are using Debian Squeeze, you will need to enable backports

    apt-get install vcsh

#### 4.1.2.2 Arch Linux ####

vcsh is availabe via [AUR](https://aur.archlinux.org/packages.php?ID=54164)
and further documentation about the use of AUR is available
[on Arch's wiki](https://wiki.archlinux.org/index.php/Arch_User_Repository).

    cd /var/abs/local/
    wget https://aur.archlinux.org/packages/vc/vcsh-git/vcsh-git.tar.gz
    tar xfz vcsh-git.tar.gz
    cd vcsh-git
    makepkg -s
    pacman -U vcsh*.pkg.tar.xz

#### 4.1.2.3 From source ####

If your version of mr is older than version 1.07, make sure to put

    include = cat /usr/share/mr/vcsh

into your .mrconfig .

    # choose a location for your checkout
    cd $HOME
    mkdir -p ~/work/git
    git clone git://github.com/RichiH/vcsh.git
    cd vcsh
    ln -s vcsh /usr/local/bin                       # or add it to your PATH
    cd

#### 4.1.3 Clone the Template ####

    vcsh clone git://github.com/RichiH/vcsh_mr_template.git mr

#### 4.1.4 Enable Your Test Repository ####

    mv ~/.zsh   ~/zsh.bak
    mv ~/.zshrc ~/zshrc.bak
    cd $XDG_CONFIG_HOME/mr/config.d/
    ln -s ../available.d/zsh.vcsh .  # link, and thereby enable, the zsh repository
    cd
    mr up

#### 4.1.5 Set Up Your Own Repositories ####

Now, it's time to edit the template config and fill it with your own remotes:

    vim $XDG_CONFIG_HOME/mr/available.d/mr.vcsh
    vim $XDG_CONFIG_HOME/mr/available.d/zsh.vcsh

And then create your own stuff:

    vcsh init foo
    vcsh run foo git add -f bar baz quux
    vcsh run foo git remote add origin git://quuux
    vcsh run foo git commit
    vcsh run foo git push

    cp $XDG_CONFIG_HOME/mr/available.d/mr.vcsh $XDG_CONFIG_HOME/mr/available.d/foo.vcsh
    vim $XDG_CONFIG_HOME/mr/available.d/foo.vcsh # add your own repo

Done!

### 4.2 The Steal-from-Template Way ###

You're welcome to clone the example repository:

    vcsh clone git://github.com/RichiH/vcsh_mr_template.git mr
    # make sure 'include = cat /usr/share/mr/vcsh' points to an exiting file
    vim .mrconfig

Look around in the clone. It should be reasonably simple to understand. If not,
poke me, RichiH, on Freenode (query) or OFTC (#vcs-home).


### 4.3 The Manual Way ###

This is how my old setup procedure looked like. Adapt it to your own style or
copy mine verbatim, either is fine.

    # Create workspace
    mkdir -p ~/work/git
    cd !$

    # Clone vcsh and make it available
    git clone git://github.com/RichiH/vcsh.git vcsh
    sudo ln -s ~/work/git/vcsh/vcsh /usr/bin/local
    hash -r

Grab my mr config. see below for details on how I set this up

    vcsh clone ssh://<remote>/mr.git
    cd $XDG_CONFIG_HOME/mr/config.d/
    ln -s ../available.d/* .


mr is used to actually retrieve configs, etc

    ~ % cat ~/.mrconfig
    [DEFAULT]
    # adapt /usr/share/mr/vcsh to your system if needed
    include = cat /usr/share/mr/vcsh
    include = cat $XDG_CONFIG_HOME/mr/config.d/*
    ~ % echo $XDG_CONFIG_HOME
    /home/richih/.config
    ~ % ls $XDG_CONFIG_HOME/mr/available.d # random selection of my repos
    git-annex gitk.vcsh git.vcsh ikiwiki mr.vcsh reportbug.vcsh snippets.git wget.vcsh zsh.vcsh
    ~ %
    # then simply ln -s whatever you want on your local machine from
    # $XDG_CONFIG_HOME/mr/available.d to $XDG_CONFIG_HOME/mr/config.d
    ~ % cd
    ~ % mr -j 5 up

# 5 Usage #

### 5.1 Keeping repositories Up-to-Date ###

This is the beauty of it all. Once you are set up, just run:

    mr up
    mr push

Neat.

### 5.1 Making Changes ###

After you have made some changes, for which you would normally use `git add`
and `git commit`, use the vcsh wrapper (like above):

    vcsh run foo git add -f bar baz quux
    vcsh run foo git commit
    vcsh run foo git push

By the way, you'll have to use -f/--force flag with git-add because all files
will be ignored by default. This is to show you only useful output when running
git-status. A fix for this problem is being worked on.

### 5.3 Using vcsh without mr ###

vcsh encourages you to use [mr] [1]. It helps you manage a large number of
repositories by running the necessary vcsh commands for you. You may choose not
to use mr, in which case you will have to run those commands manually or by
other means.

#### A Few Examples ####

To initialize a new repository: `vcsh init zsh`

To clone a repository: `vcsh clone ssh://<remote>/zsh.git`

To interact with a repository, use the regular Git commands, but prepend them
with `vcsh run $repository_name`. For example:

    vcsh run zsh git status
    vcsh run zsh git add -f .zshrc
    vcsh run zsh git commit

Obviously, without mr keeping repositories up-to-date, it will have to be done
manually. Alternatively, you could try something like this:

    for repo in `vcsh list`; do
        vcsh run $repo git pull;
    done


[mr]: http://kitenet.net/~joey/code/mr/
[talks]: http://richardhartmann.de/talks/
[vcsh]: https://github.com/RichiH/vcsh
[vcs-home-list]: http://lists.madduck.net/listinfo/vcs-home