Hi, Niklas Eklund schreef op za 15-01-2022 om 08:35 [+0000]: > +      (modify-phases %standard-phases > +        (add-before 'install 'install-dtache-env > +          (lambda* (#:key outputs #:allow-other-keys) > +            (let* ((out  (assoc-ref outputs "out")) > +                   (bin  (string-append out "/bin"))) > +              (mkdir-p bin) > +              (copy-file "dtache-env" > +                         (string-append bin "/dtache-env")))))))) FWIW you can eliminate (#:key outputs #:allow-other-keys) here: ,#~(modify-phases %standard-phases (add-before 'install 'install-dtache-env (lambda _ (let ((bin (string-append #$output "/bin))) (mkdir-p bin) (copy-file "dtache-env" (string-append bin "/dtache-env")))))))) YMMV on whether that's an improvement or not -- technically they are equivalent. Greetings, Maxime.