How do I enter file paths into a link? (Both local and UNC Names)

The "correct" link format is file:/// followed by the path to the file, using forward slashes throughout:

[[file:///home/user/somefile]]
[[file:///C:/somefile.txt]]

Windows shares can be referenced in a link, with some restrictions / considerations:

• Write the link using file:/// (3 forward slashes), followed by the UNC name \\server\path\filename
  • Technically the forward slash should be used throughout the link, but the backslash works on windows platforms
  • Some browsers appear to auto-convert a single slash file:/some/file to the required 3-slashes file:///some/file. It's probably safer to use the 3 slash format.

[[file://///myserver/path/somefile.doc]]

• Under some conditions, embedded spaces must be encoded as %20
  • Simple square bracket links without link text must have embedded spaces encoded
    • [[file:///\\path\file with spaces][link text]] does not need to be encoded because it has the explicit link text.
    • [[file:///\\path\file%20with%20spaces]] must be encoded as shown here.
  • Explicit HTML tags must have embedded spaces encoded.
    • <a href="file:///\\server\My%20Documents\SomeFile>Link to file</a>

• WysiwygPlugin Version 1.13 properly preserves the %20 encoded spaces and will also encode spaces when saving the topic. Earlier versions of WysiwygPlugin might cause issues.

• It's the client that reads the file, not the server. so the client must be part of the Windows domain and have access to the file.

• Local Links are a significant security exposure and are blocked by recent browsers. Enable at your own risk.
  • Internet Explorer 8 & 9 (and possibly IE7) will only allow clickable links that are from sites in the Intranet or Trusted zone.
  • Firefox blocks these links by default. See this mozillaZine article for details on why they are blocked and how to enable local links.
  • The NoScript Firefox add-on can permit local links on trusted sites.
  • Chrome and Firefox also have a "LocalLinks" plugin that can enable linking to local files.