= Trac Links =
As you might have guessed, TracLinks are a very fundamental feature of Trac.

They allow hyperlinking between Trac entities (tickets, reports, changesets, Wiki
pages, milestones and source files) from anywhere WikiFormatting is used.

TracLinks are generally of the form '''type:id''' (where ''id'' represents the
number, name or path of the item) though some frequently used kinds of items
also have short-hand notations.

Some examples:
 * Tickets: '''!#1''' or '''!ticket:1'''
 * Reports: '''!{1}''' or '''!report:1'''
 * Changesets: '''!r1''', '''![1]''' or '''!changeset:1'''
 * Revision log: '''!r1:3''', '''![1:3]''' or '''!log:@1:3''', '''!log:trunk@1:3'''
 * Diffs: '''!diff:@1:3''', '''!diff:tags/trac-0.9.2/wiki-default//tags/trac-0.9.3/wiki-default''' or '''!diff:trunk/trac@3538//sandbox/vc-refactoring@3539'''
 * Wiki pages: '''CamelCase''' or '''!wiki:CamelCase'''
 * Milestones: '''!milestone:1.0'''
 * Attachment: '''!attachment:ticket:944:attachment.1073.diff'''
 * Files: '''!source:trunk/COPYING'''
 * A specific file revision: '''!source:/trunk/COPYING@200'''
 * A particular line of a specific file revision: '''!source:/trunk/COPYING@200#L25'''
Display:
 * Tickets: #1 or ticket:1
 * Reports: {1} or report:1
 * Changesets: r1, [1] or changeset:1
 * Revision log: r1:3, [1:3] or log:@1:3, log:trunk@1:3
 * Diffs: diff:@20:30, diff:tags/trac-0.9.2/wiki-default//tags/trac-0.9.3/wiki-default or diff:trunk/trac@3538//sandbox/vc-refactoring/trac@3539
 * Wiki pages: CamelCase or wiki:CamelCase
 * Milestones: milestone:1.0
 * Attachment: attachment:ticket:944:attachment.1073.diff
 * Files: source:trunk/COPYING
 * A specific file revision: source:/trunk/COPYING@200
 * A particular line of a specific file revision: source:/trunk/COPYING@200#L25

'''Note:''' The wiki:CamelCase form is rarely used, but it can be convenient to refer to
pages whose names do not follow WikiPageNames rules, i.e., single words,
non-alphabetic characters, etc. See WikiPageNames for more about features specific to Wiki page names Trac links.

Trac links using the full (non-shorthand) notation can also be given a custom
link title like this:

{{{
[ticket:1 This is a link to ticket number one].
}}}

Display: [ticket:1 This is a link to ticket number one].

If the title is be omitted, only the id (the part after the colon) is displayed:

{{{
[ticket:1]
}}}

Display: [ticket:1]

`wiki` is the default if the namespace part of a full link is omitted (''since [milestone:0.10]''):

{{{
[SandBox the sandbox]
}}}

Display: [wiki:SandBox the sandbox]

It might seem a simple enough concept at a glance, but actually allows quite a complex network of information. In practice, it's very intuitive and simple to use, and we've found the "link trail" extremely helpful to better understand what's happening in a project or why a particular change was made.

== attachment: links ==

The link syntax for attachments is as follows:
 * !attachment:the_file.txt creates a link to the attachment the_file.txt of the current object
 * !attachment:wiki:MyPage:the_file.txt creates a link to the attachment the_file.txt of the !MyPage wiki page
 * !attachment:ticket:753:the_file.txt creates a link to the attachment the_file.txt of the ticket 753

== source: links ==

The default behavior for a source:/some/path link is to open the directory browser 
if the path points to a directory and otherwise open the log view. 
It's also possible to link directly to a specific revision of a file like this: source:/some/file@123 
or like this to link to the latest revision: source:/some/file@latest.
If the revision is specified, one can even link to a specific line number: source:/some/file@123#L10 

== search: and query: links ==

See TracSearch#SearchLinks and TracQuery#UsingTracLinks


== Server-relative links ==

It is often necessary to link to objects on your server that have no built-in
Trac linking mechanism, such as static resources, a `/register` page, etc. This
can be achieved by simply using either an absolute path from the server root, 
or a relative link from the Trac environments base:

{{{
[../newticket newticket]
[/ home]
}}}

Display: [../newticket newticket] [/ home]

== Quoting space in TracLinks ==

Immediately after a TracLinks prefix, targets containing space characters should
be enclosed in a pair of quotes or double quotes.
Examples:
 * !wiki:"The whitespace convention"
 * !attachment:'the file.txt' or
 * !attachment:"the file.txt" 
 * !attachment:"ticket:123:the file.txt" 

== Where to use TracLinks ==
You can use TracLinks in:

 * Source code (Subversion) commit messages
 * Wiki pages
 * Full descriptions for tickets, reports and milestones

and any other text fields explicitly marked as supporting WikiFormatting.

== Escaping Links ==

To prevent parsing of a !TracLink, you can escape it by preceding it with a '!' (exclamation mark).
{{{
 !NoLinkHere.
 ![42] is not a link either.
}}}

Display:
 !NoLinkHere.
 ![42] is not a link either.

----
See also: WikiFormatting, TracWiki, WikiPageNames