Running newLISP scripts in BBEdit/TextWrangler

If you’re using BBEdit or TextWrangler on MacOS X, it’s easy to write newLISP scripts that process text windows. Store your scripts in the ~/Library/Application Support/BBEdit/Unix Support/Unix Filters/ folder.

A basic script looks like this:

#!/usr/bin/newlisp
(dolist (file-name (2 (main-args)))
    (set 'file (open file-name "read"))
    (while (read-line file)
        (println (current-line)))
    (close file))
(exit)

Notice the 2 in (2 (main-args)): this extracts the name of the file from the list of arguments that BBEdit passes to newLISP. The arguments are as follows:

1. argument 0: “/usr/bin/newlisp”
2. argument 1: path to the Unix filter
3. argument 2: path to BBEdit’s temporary copy of the document

So this script processes argument 2, the temporary version of your current document that BBEdit creates.

As it stands, this script simply replaces each line of the current window with itself. To make it do something more useful, just insert more code:

(dolist (file-name (2 (main-args))) ; 2
    (set 'file (open file-name "read"))
    (while (read-line file)
        (println
            (replace {(\d+)}
                (current-line)
                (string (add (int $1) 1)) 0 )))
    (close file))
(exit)

This adds 1 to every number in the text.

By the way, BBEdit/TextWrangler can run Unix filters on the current selection only, not just the whole file.