On Sat, Dec 25, 2021 at 04:17:32PM -0500, Raghav Gururajan via Guix-patches via wrote:
> Hi Ricardo!
> 
> > --8<---------------cut here---------------start------------->8---
> > (substitute* "hw-probe.pl"
> >    (("Cmd\\(\"([^\"]+)" _ command)
> >     (string-append "Cmd(\"" (which command))))
> > --8<---------------cut here---------------end--------------->8---
> 
> Thanks for the snippet and explanation.
> 
> I am wondering these,
> [1] Does require import of specific modules?
> [2] If `(which command)`'s output is empty, will it return #f?

For 2, looks like yes

(ins)efraim@3900XT ~$ which -a svn
which: no svn in (/home/efraim/Applications/.bin:/gnu/store/4iyar3w7k30b5j13v9cf5gmiz5livkyj-enlightenment-0.24.2/bin:/run/setuid-programs:/home/efraim/.config/guix/current/bin:/home/efraim/.guix-profile/bin:/home/efraim/.guix-profile/sbin:/run/current-system/profile/bin:/run/current-system/profile/sbin)
(ins)efraim@3900XT ~$ guile
GNU Guile 3.0.7
Copyright (C) 1995-2021 Free Software Foundation, Inc.

Guile comes with ABSOLUTELY NO WARRANTY; for details type `,show w'.
This program is free software, and you are welcome to redistribute it
under certain conditions; type `,show c' for details.

Enter `,help' for help.
(ins)scheme@(guile-user)> (use-modules (guix build utils))
(ins)scheme@(guile-user)> (which "svn")
$1 = #f
(ins)scheme@(guile-user)>


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Efraim Flashner   <efraim@flashner.co.il>   רנשלפ םירפא
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