How to customise file type to syntax associations in Sublime Text?

In Sublime Text (confirmed in both v2.x and v3.x) there is a menu command:

View -> Syntax -> Open all with current extension as ...

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I've found the answer (by further examining the Sublime 2 config files structure):

I was to open

~/.config/sublime-text-2/Packages/Scala/Scala.tmLanguage

And edit it to add sbt (the extension of files I want to be opened as Scala code files) to the array after the fileTypes key:

<dict>
  <key>bundleUUID</key>
  <string>452017E8-0065-49EF-AB9D-7849B27D9367</string>
  <key>fileTypes</key>
  <array>
    <string>scala</string>
    <string>sbt</string>
  <array>
  ...

PS: May there be a better way, something like a right place to put my customizations (insted of modifying packages themselves), I'd still like to know.

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I put my customized changes in the User package:

*nix: ~/.config/sublime-text-2/Packages/User/Scala.tmLanguage
*Windows: %APPDATA%\Sublime Text 2\Packages\User\Scala.tmLanguage

Which also means it's in JSON format:

{
  "extensions":
  [
    "sbt"
  ]
}

This is the same place the

View -> Syntax -> Open all with current extension as ...

menu item adds it (creating the file if it doesn't exist).

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For ST3

$language = "language u wish"

If exists, open ~/.config/sublime-text-3/Packages/User/*$language*.sublime-settings

else just create it.

And set

{
    "extensions":
    [
        "*yourextension*"
    ]
}

This way allows you to enable syntax for composite extensions (e.g. sql.mustache, js.php, etc ... )

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There's an excellent plugin called ApplySyntax (previously DetectSyntax) that provides certain other niceties for file-syntax matching. allows regex expressions etc.

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There is a quick method to set the syntax: Ctrl+Shift+P,then type in the input box

ss + （which type you want set）

eg: ss html +Enter

and ss means "set syntax"

it is really quicker than check in the menu's checkbox.

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