Text Filters accept the selection range (or entire document, if no selection) as input, and return text that replaces the selection range (or document). They may contain Unix scripts, AppleScript files, text factories, and Automator workflows. The selected text (or front document contents, if there is no selection) is passed as `argv` to Unix executables, as a string to text factories, as a reference to a `RunFromBBEdit` entry point in AppleScripts, as text input to Automator workflows, and as a source to text factories.
Starting with BBEdit 10.1, text input is passed to Unix executables via `stdin`, not `argv`.
Text filters live in ~/Library/Application Support/BBEdit/Text Filters. To use a Text Filter, select Apply Text Filter from the Text menu.