MSG File Format

MSG files are indexed text files. They contain in-game messages, character and item dialogues, and are located in the text\english\game and text\english\dialog folders, respectively.

Structure

Each indexed text line has the format: "{}{}{}"

• The first set of curly braces "{}" indicate the line index (number) in decimal format
• The second set of braces (optionally) indicates the name of an ACM sound file
• The third set of braces contain the text to be displayed (dialogue box or observation window)

Dialogue Line Number
       |
       |
  +----+    ACM sound file name
  |                 |
  |                 |
  |            +----+                 Displayed message (dialogue box or observation window)
  |            |                                |
  |            |                                |
  |            |                           +----+
  |            |                           |
  v            v                           v

{100}  {deadbrahmin001}   {You see a horribly mutilated, two-headed cow. Hamburgers, anyone?}

Notes

• The length of the lines between the braces cannot exceed 1024 characters
• The length of a single word cannot exceed 53 characters (max width of the in-game dialog window), the rest is not displayed
• Linebreaks inside the braces are allowed ^*
• Linebreaks are ignored by game engine. That is, if you do

{Hi

there}

in msg, it will be displayed as "Hithere" in-game.

• At the end of the file there is a blank line (with no characters in it)
• The game only looks for text within braces, which allows leaving comments in between the indexed lines
• Comments are usually preceded by a "#", or a pound symbol, unlike Fallout's scripting language, SSL, which uses two slashes "//" ^**
• Sound files are generally only used in dialog with 'talking heads'
• Index is supposed to be unique. If it's not unique, only the latest string with matching index is used by the game.

^* However, a trailing portion of the string must contain at least one non-space character before the last brace. Otherwise, the game will crash.
^** The Fallout engine itself treats everything outside of the braces as comments (ignores them). However, comment mark-ups could be required by some of the external modding tools.

Example

Taken from AHHAKUN.MSG - Hakunin's message / dialogue file (Fallout 2)

{100}{}{Before you stands Hakunin, the village shaman. He appraises you with his crazy eyes from somewhere 
in the world only he inhabits.....}
{101}{}{You see Hakunin lying on the ground. He's badly wounded.}
{102}{}{You see Hakunin. He's very near death.}
{103}{}{Hakunin is badly burned. He smells like roast chicken, looks like burnt meatloaf, and you don't know 
how he's managed to stay alive this long.}

#Commentary: the following line of text plays a sound (the sound file is hak001.acm)

{104}{hak001}{Greetings, Chosen. Why does the earth before me warm to the touch of your passing?}
{105}{}{Uh?}

Open with

.MSG files can be opened with any simple text-editing programs, like Notepad or WordPad. Additionally, the Fallout Script Editor has a function that allows you to open and edit message files as well.

Note: Editing in a more feature-rich text editor such as Microsoft Word should not be a problem in theory, but should be treated with care unless you opt to save the file in Plain Text Format after you're done making changes. Programs such as Word can use characters that Fallout could (potentially) not parse properly. For example, Word automatically changing three periods to one 'rich text' character (an elipses).

Some files that ship with Fallout 1 do have these characters and seem to work properly, but it's something to keep in mind when editing. Assumedly the same applies to Fallout 2 {citation needed}

TeamX document

Original document at teamx.ru (in russian)