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= Repository =

''(for a short intro of the basic concepts of Mercurial, see [[UnderstandingMercurial]])''

Strictly speaking, the term '''repository''' refers to the directory named `.hg` (dot hg) in the ''repository root directory''. The repository root directory is the parent directory of the `.hg` directory. Mercurial stores its internal data structures – the metadata – inside that `.hg` directory.

All of the files and directories that coexist with the `.hg` directory in the repository root are said to live in the [[WorkingDirectory|working directory]].

An easy way to remember the distinction is that the repository contains the history of your project, while the working directory contains a snapshot of your project at a particular point in history.

Local Mercurial repositories are addressed by specifying the path to the repository root (global option `-R` for commands).

Sometimes Mercurial users and developers also use the term "repository" when referring to the repository root. But strictly speaking, the `.hg` directory is the "real" repository.

<<TableOfContents>>


== Creation ==

Repositories can be [[Cmd:clone|cloned]] with {{{hg clone}}}, which creates a copy of an existing repository. If possible,
Mercurial uses hardlinks to save space and speedup the cloning (see HardlinkedClones).

An existing, already populated but yet untracked directory can be transformed into a repository with {{{hg init}}}, which creates and initializes the {{{.hg}}} subdirectory.


== Tracking files ==

A file in the working directory that shall be tracked by Mercurial must be added with {{{hg add}}}. [[LocalModifications|Local modifications]] to tracked files in the working directory can be [[Cmd:commit|committed]] with {{{hg commit}}}, which adds a new [[ChangeSet|changeset]] to the repository by recording it in the {{{.hg}}} directory.

The working directory can be restored with {{{hg update}}} to any previously committed state by specifying the requested changeset with its [[ChangeSetID|changeset ID]] (see [[Cmd:update|update]]). Use {{{hg parents}}} to see the currently checked
out revision (see [[Cmd:parents|parents]]).

The last commit in a repository can be undone with {{{hg rollback}}} (see [[Cmd:rollback|rollback]]).


== Transferring changesets ==

Changesets can be transferred from one repository to another with {{{hg pull}}}, {{{hg push}}}, {{{hg export}}} and {{{hg import}}} (see [[Cmd:pull]], [[Cmd:push]], [[Cmd:export]], [[Cmd:import]], [[CommunicatingChanges]]).


== Checking integrity ==

Checking the internal integrity of a repository (the contents of {{{.hg}}}) can be done with {{{hg verify}}}.


== Structure ==

The {{{.hg}}} directory of a repository contains (incomplete listing):

 * The [[Manifest|manifest]] &mdash; Files {{{.hg/store/00manifest.i}}} and {{{.hg/store/00manifest.d}}}
    Describes the file contents of the repository at a particular changeset ID. Stored in [[Revlog|revlog]] format.
 * The changelog &mdash; Files {{{.hg/store/00changelog.i}}} and {{{.hg/store/00changelog.d}}}
    Contains all changesets. Stored in revlog format.
 * A revlog per tracked file &mdash; Files {{{.hg/store/data/<encoded path>.i}}} and {{{.hg/store/data/<encoded path>.d}}}
    {{{<encoded path>}}} is the path of the tracked file in the working directory, encoded according to [[CaseFoldingPlan]].
 * The [[DirState|dirstate]] &mdash; File {{{.hg/dirstate}}}
    Tracks various information about the working directory.
 * The [[RequiresFile|requires file]] &mdash; File {{{.hg/requires}}}
    Specifies the capabilities needed by a client to access this repository

Note that for small revlogs, the revlog data file ({{{*.d}}}) may be missing, because its content may be interleaved into the corresponding index file ({{{*.i}}}) (see also [[RevlogNG]]).


== Backup ==

Backing up a repository can be done by using push/pull/clone to a backup repository. A repository which is not actively written to (by other processes concurrently running on the computer) can be backed-up by backing-up the repo directory using normal directory/file backup procedures (like tar, zip, etc). The {{{.hg}}} directory is [[CaseFolding|case folding]] tolerant, which means, it can for example be copied onto a FAT filesystem (see also [[BackUp]], [[CaseFoldingPlan]]).


== See also ==

 * [[RepositoryNaming]]
 * [[PublishingRepositories]]
 * [[SharedRepository]]
 * [[Subrepository]]
 * [[RepositoryCorruption]]
 * [[UpgradingMercurial]]

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[[FrenchRepository|Français]]