Hello guixers, 
For an even more foolproof experience when trying [ https://guix.gnu.org/cookbook/en/html_node/Reproducible-profiles.html | https://guix.gnu.org/cookbook/en/html_node/Reproducible-profiles.html ] (which already goes very smoothly), the command 
`mkdir "$GUIX_EXTRA"/my-project` (fourth line) could add the option `-p` (i.e. `mkdir -p "$GUIX_EXTRA"/my-project`). 

Keep hacking! 

Luca 

-- 
Luca CIRROTTOLA 
Research software engineer @ INRIA center of the university of Bordeaux 
Personal webpage: [ https://lcirrottola.github.io/ | https://lcirrottola.github.io/ ] 
Tel: +33 5 2 4 57 41 21 
200 Avenue de la Vieille Tour 
33405 Talence cedex 
France