# Using Additional Features

Mercurial has the ability to add new features through the use of extensions. Extensions may add new commands, add options to existing commands, change the default behavior of commands, or implement hooks.

To enable the "foo" extension, either shipped with Mercurial or in the Python search path, create an entry for it in your configuration file, like this:

    [extensions]
    foo =

You may also specify the full path to an extension:

    [extensions]
    myfeature = ~/.hgext/myfeature.py

See `hg help config` for more information on configuration files.

Extensions are not loaded by default for a variety of reasons: they can increase startup overhead; they may be meant for advanced usage only; they may provide potentially dangerous abilities (such as letting you destroy or modify history); they might not be ready for prime time; or they may alter some usual behaviors of stock Mercurial. It is thus up to the user to activate extensions as needed.

To explicitly disable an extension enabled in a configuration file of broader scope, prepend its path with !:

    [extensions]
    # disabling extension bar residing in /path/to/extension/bar.py
    bar = !/path/to/extension/bar.py
    # ditto, but no path was supplied for extension baz
    baz = !

disabled extensions:

> acl: | hooks for controlling repository access
> blackbox: | log repository events to a blackbox for debugging
> bugzilla: | hooks for integrating with the Bugzilla bug tracker
> censor: | erase file content at a given revision
> churn: | command to display statistics about repository history
> clonebundles: | advertise pre-generated bundles to seed clones
> closehead: | close arbitrary heads without checking them out first
> convert: | import revisions from foreign VCS repositories into Mercurial
> eol: | automatically manage newlines in repository files
> extdiff: | command to allow external programs to compare revisions
> factotum: | http authentication with factotum
> fastexport: | export repositories as git fast-import stream
> githelp: | try mapping git commands to Mercurial commands
> gpg: | commands to sign and verify changesets
> hgk: | browse the repository in a graphical way
> highlight: | syntax highlighting for hgweb (requires Pygments)
> histedit: | interactive history editing
> keyword: | expand keywords in tracked files
> largefiles: | track large binary files
> mq: | manage a stack of patches
> notify: | hooks for sending email push notifications
> patchbomb: | command to send changesets as (a series of) patch emails
> rebase: | command to move sets of revisions to a different ancestor
> relink: | recreates hardlinks between repository clones
> schemes: | extend schemes with shortcuts to repository swarms
> share: | share a common history between several working directories
> transplant: | command to transplant changesets from another branch
> win32mbcs: | allow the use of MBCS paths with problematic encodings
> zeroconf: | discover and advertise repositories on the local network