Enter an environment where Emacs and emacs-guix are available:

    guix environment --ad-hoc emacs emacs-guix

Then run:

    emacs -q --batch -l indent-package-expr.el  bowtie bla blast+

This will properly indent the package expressions for “bowtie” and
“blast+”, and it will ignore “bla”, because that package doesn’t exist.

This is probably a little heavy-weight because it depends on emacs-guix,
which starts a Guile REPL, but other than that it seems to work fine.

--
Ricardo

GPG: BCA6 89B6 3655 3801 C3C6  2150 197A 5888 235F ACAC
http://elephly.net