On Mon, 15 May 2017 17:59:42 +0200
Marius Bakke <mbakke@fastmail.com> wrote:

> Christopher Baines <mail@cbaines.net> writes:
> > +         (add-after 'install 'wrap-tailon-path
> > +                    (lambda* (#:key inputs outputs
> > #:allow-other-keys)
> > +                      (let ((out (assoc-ref outputs "out")))
> > +                        (substitute* (find-files out "commands.py")
> > +                          (("self\\.first_in_path\\('grep'\\)")
> > +                           (string-append"'" (which "grep") "'"))
> > +                          (("self\\.first_in_path\\('gawk',
> > 'awk'\\)")
> > +                           (string-append"'" (which "gawk") "'"))
> > +                          (("self\\.first_in_path\\('gsed',
> > 'sed'\\)")
> > +                           (string-append"'" (which "sed") "'"))
> > +                          (("self\\.first_in_path\\('gtail',
> > 'tail'\\)")
> > +                           (string-append"'" (which "tail") "'")))
> > +                        #t))))))  
> 
> Is there any particular reason this phase runs after 'install'? I
> think we should try to avoid modifying files after they have been
> copied to the store, but if doing this substitution earlier is
> difficult I guess it's okay with a comment.

No, I just put it there by default, but I can see why doing the
substitution earlier would be better. I've sent another patch that
moves it to after the unpack phase.