Mercurial allows you to customize output of commands through

templates. You can either pass in a template or select an existing

template-style from the command line, via the --template option.

You can customize output for any "log-like" command: log,

outgoing, incoming, tip, parents, and heads.

Some built-in styles are packaged with Mercurial. These can be listed

with :hg:`log --template list`. Example usage::

    $ hg log -r1.0::1.1 --template changelog

A template is a piece of text, with markup to invoke variable

expansion::

    $ hg log -r1 --template "{node}\n"

    b56ce7b07c52de7d5fd79fb89701ea538af65746

Keywords

========

Strings in curly braces are called keywords. The availability of

keywords depends on the exact context of the templater. These

keywords are usually available for templating a log-like command:

.. keywordsmarker

The "date" keyword does not produce human-readable output. If you

want to use a date in your output, you can use a filter to process

it. Filters are functions which return a string based on the input

variable. Be sure to use the stringify filter first when you're

applying a string-input filter to a list-like input variable.

You can also use a chain of filters to get the desired output::

   $ hg tip --template "{date|isodate}\n"

   2008-08-21 18:22 +0000

Filters

=======

List of filters:

.. filtersmarker

Note that a filter is nothing more than a function call, i.e.

``expr|filter`` is equivalent to ``filter(expr)``.

Functions

=========

In addition to filters, there are some basic built-in functions:

.. functionsmarker

Operators

=========

We provide a limited set of infix arithmetic operations on integers::

  + for addition

  - for subtraction

  * for multiplication

  / for floor division (division rounded to integer nearest -infinity)

Division fulfills the law x = x / y + mod(x, y).

Also, for any expression that returns a list, there is a list operator::

    expr % "{template}"

As seen in the above example, ``{template}`` is interpreted as a template.

To prevent it from being interpreted, you can use an escape character ``\{``

or a raw string prefix, ``r'...'``.

The dot operator can be used as a shorthand for accessing a sub item:

- ``expr.member`` is roughly equivalent to ``expr % '{member}'`` if ``expr``

  returns a non-list/dict. The returned value is not stringified.

- ``dict.key`` is identical to ``get(dict, 'key')``.

Aliases

=======

New keywords and functions can be defined in the ``templatealias`` section of

a Mercurial configuration file::

  <alias> = <definition>

Arguments of the form `a1`, `a2`, etc. are substituted from the alias into

the definition.

For example,

::

  [templatealias]

  r = rev

  rn = "{r}:{node|short}"

  leftpad(s, w) = pad(s, w, ' ', True)

defines two symbol aliases, ``r`` and ``rn``, and a function alias

``leftpad()``.

It's also possible to specify complete template strings, using the

``templates`` section. The syntax used is the general template string syntax.

For example,

::

  [templates]

  nodedate = "{node|short}: {date(date, "%Y-%m-%d")}\n"

defines a template, ``nodedate``, which can be called like::

  $ hg log -r . -Tnodedate

A template defined in ``templates`` section can also be referenced from

another template::

  $ hg log -r . -T "{rev} {nodedate}"

but be aware that the keywords cannot be overridden by templates. For example,

a template defined as ``templates.rev`` cannot be referenced as ``{rev}``.

A template defined in ``templates`` section may have sub templates which

are inserted before/after/between items::

  [templates]

  myjson = ' {dict(rev, node|short)|json}'

  myjson:docheader = '\{\n'

  myjson:docfooter = '\n}\n'

  myjson:separator = ',\n'

Examples

========

Some sample command line templates:

- Format lists, e.g. files::

   $ hg log -r 0 --template "files:\n{files % '  {file}\n'}"

- Join the list of files with a ", "::

   $ hg log -r 0 --template "files: {join(files, ', ')}\n"

- Join the list of files ending with ".py" with a ", "::

   $ hg log -r 0 --template "pythonfiles: {join(files('**.py'), ', ')}\n"

- Separate non-empty arguments by a " "::

   $ hg log -r 0 --template "{separate(' ', node, bookmarks, tags}\n"

- Modify each line of a commit description::

   $ hg log --template "{splitlines(desc) % '**** {line}\n'}"

- Format date::

   $ hg log -r 0 --template "{date(date, '%Y')}\n"

- Display date in UTC::

   $ hg log -r 0 --template "{localdate(date, 'UTC')|date}\n"

- Output the description set to a fill-width of 30::

   $ hg log -r 0 --template "{fill(desc, 30)}"

- Use a conditional to test for the default branch::

   $ hg log -r 0 --template "{ifeq(branch, 'default', 'on the main branch',

   'on branch {branch}')}\n"

- Append a newline if not empty::

   $ hg tip --template "{if(author, '{author}\n')}"

- Label the output for use with the color extension::

   $ hg log -r 0 --template "{label('changeset.{phase}', node|short)}\n"

- Invert the firstline filter, i.e. everything but the first line::

   $ hg log -r 0 --template "{sub(r'^.*\n?\n?', '', desc)}\n"

- Display the contents of the 'extra' field, one per line::

   $ hg log -r 0 --template "{join(extras, '\n')}\n"

- Mark the active bookmark with '*'::

   $ hg log --template "{bookmarks % '{bookmark}{ifeq(bookmark, active, '*')} '}\n"

- Find the previous release candidate tag, the distance and changes since the tag::

   $ hg log -r . --template "{latesttag('re:^.*-rc$') % '{tag}, {changes}, {distance}'}\n"

- Mark the working copy parent with '@'::

   $ hg log --template "{ifcontains(rev, revset('.'), '@')}\n"

- Show details of parent revisions::

   $ hg log --template "{revset('parents(%d)', rev) % '{desc|firstline}\n'}"

- Show only commit descriptions that start with "template"::

   $ hg log --template "{startswith('template', firstline(desc))}\n"

- Print the first word of each line of a commit message::

   $ hg log --template "{word(0, desc)}\n"