Windows Command line (.cmd,.bat)

You can add your own syntax definitions to Textastic using TextMate bundles.

I've created a bundle derived from the syntax file at http://adamv.googlecode.com/svn/editors/e/bundles/Windows%20Cmd.tmbundle/Syntaxes/Shell%20Script.tmLanguage

You can download the bundle here:
http://www.textasticapp.com/support/Batch.tmbundle.zip

Have a look at the manual to see how can you install it in Textastic:
http://www.textasticapp.com/v4/manual/lessons/How_can_I_add_my_own_syntax_definitions__themes_and_templates.html

Once you install it, the "Batch File" syntax should be automatically selected when you open .bat or .cmd files.

This syntax definition will be built-in in the next update.