# Template Usage

Contents

- Keywords
- Filters
- Functions
- Operators
- Aliases
- Examples

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:

_fast_rank: | the rank of a changeset if cached The rank of a revision is the size of the sub-graph it defines as a head. Equivalently, the rank of a revision r is the size of the set ancestors(r), r included.
activebookmark: | String. The active bookmark, if it is associated with the changeset.
author: | Alias for `{user}`
bisect: | String. The changeset bisection status.
bookmarks: | List of strings. Any bookmarks associated with the changeset. Also sets 'active', the name of the active bookmark.
branch: | String. The name of the branch on which the changeset was committed.
changessincelatesttag:
| Integer. All ancestors not in the latest tag.
children: | List of strings. The children of the changeset.
date: | Date information. The date when the changeset was committed.
desc: | String. The text of the changeset description.
diffstat: | String. Statistics of changes with the following format: "modified files: +added/-removed lines"
extras: | List of dicts with key, value entries of the 'extras' field of this changeset.
file_adds: | List of strings. Files added by this changeset.
file_copies: | List of strings. Files copied in this changeset with their sources.
file_copies_switch:
| List of strings. Like "file_copies" but displayed only if the --copied switch is set.
file_dels: | List of strings. Files removed by this changeset.
file_mods: | List of strings. Files modified by this changeset.
files: | List of strings. All files modified, added, or removed by this changeset.
graphnode: | String. The character representing the changeset node in an ASCII revision graph.
graphwidth: | Integer. The width of the graph drawn by 'log --graph' or zero.
index: | Integer. The current iteration of the loop. (0 indexed)
latesttag: | List of strings. The global tags on the most recent globally tagged ancestor of this changeset. If no such tags exist, the list consists of the single string "null".
latesttagdistance:
| Integer. Longest path to the latest tag.
namespaces: | Dict of lists. Names attached to this changeset per namespace.
negrev: | Integer. The repository-local changeset negative revision number, which counts in the opposite direction.
node: | String. The changeset identification hash, as a 40 hexadecimal digit string.
onelinesummary: | String. A one-line summary for the ctx (not including trailing newline). The default template be overridden in command-templates.oneline-summary.
p1: | Changeset. The changeset's first parent. `{p1.rev}` for the revision number, and `{p1.node}` for the identification hash.
p2: | Changeset. The changeset's second parent. `{p2.rev}` for the revision number, and `{p2.node}` for the identification hash.
parents: | List of strings. The parents of the changeset in "rev:node" format. If the changeset has only one "natural" parent (the predecessor revision) nothing is shown.
peerurls: | A dictionary of repository locations defined in the [paths] section of your configuration file.
phase: | String. The changeset phase name.
reporoot: | String. The root directory of the current repository.
rev: | Integer. The repository-local changeset revision number.
subrepos: | List of strings. Updated subrepositories in the changeset.
tags: | List of strings. Any tags associated with the changeset.
termwidth: | Integer. The width of the current terminal.
user: | String. The unmodified author of the changeset.
verbosity: | String. The current output verbosity in 'debug', 'quiet', 'verbose', or ''.

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:

addbreaks: | Any text. Add an XHTML "<br />" tag before the end of every line except the last.
age: | Date. Returns a human-readable date/time difference between the given date/time and the current date/time.
basename: | Any text. Treats the text as a path, and returns the last component of the path after splitting by the path separator. For example, "foo/bar/baz" becomes "baz" and "foo/bar//" becomes "".
cbor: | Any object. Serializes the object to CBOR bytes.
commondir: | List of text. Treats each list item as file name with / as path separator and returns the longest common directory prefix shared by all list items. Returns the empty string if no common prefix exists. The list items are not normalized, i.e. "foo/../bar" is handled as file "bar" in the directory "foo/..". Leading slashes are ignored. For example, ["foo/bar/baz", "foo/baz/bar"] becomes "foo" and ["foo/bar", "baz"] becomes "".
count: | List or text. Returns the length as an integer.
dirname: | Any text. Treats the text as a path, and strips the last component of the path after splitting by the path separator.
domain: | Any text. Finds the first string that looks like an email address, and extracts just the domain component. Example: `User <user@example.com>` becomes `example.com`.
email: | Any text. Extracts the first string that looks like an email address. Example: `User <user@example.com>` becomes `user@example.com`.
emailuser: | Any text. Returns the user portion of an email address.
escape: | Any text. Replaces the special XML/XHTML characters "&", "<" and ">" with XML entities, and filters out NUL characters.
fill68: | Any text. Wraps the text to fit in 68 columns.
fill76: | Any text. Wraps the text to fit in 76 columns.
firstline: | Any text. Returns the first line of text.
hex: | Any text. Convert a binary Mercurial node identifier into its long hexadecimal representation.
hgdate: | Date. Returns the date as a pair of numbers: "1157407993 25200" (Unix timestamp, timezone offset).
isodate: | Date. Returns the date in ISO 8601 format: "2009-08-18 13:00 +0200".
isodatesec: | Date. Returns the date in ISO 8601 format, including seconds: "2009-08-18 13:00:13 +0200". See also the rfc3339date filter.
json: | Any object. Serializes the object to a JSON formatted text.
lower: | Any text. Converts the text to lowercase.
nonempty: | Any text. Returns '(none)' if the string is empty.
obfuscate: | Any text. Returns the input text rendered as a sequence of XML entities.
person: | Any text. Returns the name before an email address, interpreting it as per RFC 5322.
reverse: | List. Reverses the order of list items.
revescape: | Any text. Escapes all "special" characters, except @. Forward slashes are escaped twice to prevent web servers from prematurely unescaping them. For example, "@foo bar/baz" becomes "@foo%20bar%252Fbaz".
rfc3339date: | Date. Returns a date using the Internet date format specified in RFC 3339: "2009-08-18T13:00:13+02:00".
rfc822date: | Date. Returns a date using the same format used in email headers: "Tue, 18 Aug 2009 13:00:13 +0200".
short: | Changeset hash. Returns the short form of a changeset hash, i.e. a 12 hexadecimal digit string.
shortbisect: | Any text. Treats label as a bisection status, and returns a single-character representing the status (G: good, B: bad, S: skipped, U: untested, I: ignored). Returns single space if text is not a valid bisection status.
shortdate: | Date. Returns a date like "2006-09-18".
slashpath: | Any text. Replaces the native path separator with slash.
splitlines: | Any text. Split text into a list of lines.
stringify: | Any type. Turns the value into text by converting values into text and concatenating them.
stripdir: | Treat the text as path and strip a directory level, if possible. For example, "foo" and "foo/bar" becomes "foo".
tabindent: | Any text. Returns the text, with every non-empty line except the first starting with a tab character.
upper: | Any text. Converts the text to uppercase.
urlescape: | Any text. Escapes all "special" characters. For example, "foo bar" becomes "foo%20bar".
user: | Any text. Returns a short representation of a user name or email address.
utf8: | Any text. Converts from the local character encoding to UTF-8.

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:

config(section, name[, default]):
| Returns the requested hgrc config option as a string.
configbool(section, name[, default]):
| Returns the requested hgrc config option as a boolean.
configint(section, name[, default]):
| Returns the requested hgrc config option as an integer.
date(date[, fmt]):
| Format a date. The format string uses the Python strftime format. The default is a Unix date format, including the timezone: "Mon Sep 04 15:13:13 2006 0700".
dict([[key=]value...]):
| Construct a dict from key-value pairs. A key may be omitted if a value expression can provide an unambiguous name.
diff([includepattern [, excludepattern]]):
| Show a diff, optionally specifying files to include or exclude.
files(pattern): | All files of the current changeset matching the pattern. See `hg help patterns`.
fill(text[, width[, initialident[, hangindent]]]):
| Fill many paragraphs with optional indentation. See the "fill" filter.
filter(iterable[, expr]):
| Remove empty elements from a list or a dict. If expr specified, it's applied to each element to test emptiness.
get(dict, key): | Get an attribute/key from an object. Some keywords are complex types. This function allows you to obtain the value of an attribute on these types.
if(expr, then[, else]):
| Conditionally execute based on the result of an expression.
ifcontains(needle, haystack, then[, else]):
| Conditionally execute based on whether the item "needle" is in "haystack".
ifeq(expr1, expr2, then[, else]):
| Conditionally execute based on whether 2 items are equivalent.
indent(text, indentchars[, firstline]):
| Indents all non-empty lines with the characters given in the indentchars string. An optional third parameter will override the indent for the first line only if present.
join(list, sep):
| Join items in a list with a delimiter.
label(label, expr):
| Apply a label to generated content. Content with a label applied can result in additional post-processing, such as automatic colorization. In order to receive effects, labels must have a dot, such as log.secret or branch.active.
latesttag([pattern]):
| The global tags matching the given pattern on the most recent globally tagged ancestor of this changeset. If no such tags exist, the "{tag}" template resolves to the string "null". See `hg help revisions.patterns` for the pattern syntax.
localdate(date[, tz]):
| Converts a date to the specified timezone. The default is local date.
mailmap(author):
| Return the author, updated according to the value set in the .mailmap file
max(iterable): | Return the max of an iterable
min(iterable): | Return the min of an iterable
mod(a, b): | Calculate a mod b such that a / b + a mod b == a
pad(text, width[, fillchar=' '[, left=False[, truncate=False]]]):
| Pad text with a fill character.
relpath(path): | Convert a repository-absolute path into a filesystem path relative to the current working directory.
revset(query[, formatargs...]):
| Execute a revision set query. See `hg help revset`.
rstdoc(text, style):
| Format reStructuredText.
search(pattern, text):
| Look for the first text matching the regular expression pattern. Groups are accessible as `{1}`, `{2}`, ... in %-mapped template.
separate(sep, args...):
| Add a separator between non-empty arguments.
shortest(node, minlength=4):
| Obtain the shortest representation of a node.
startswith(pattern, text):
| Returns the value from the "text" argument if it begins with the content from the "pattern" argument.
strip(text[, chars]):
| Strip characters from a string. By default, strips all leading and trailing whitespace.
sub(pattern, replacement, expression):
| Perform text substitution using regular expressions.
subsetparents(rev, revset):
| Look up parents of the rev in the sub graph given by the revset.
word(number, text[, separator]):
| Return the nth word from a string.

# 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"