Oh my god, le hint de ouf : pour utiliser ses propres alias tout en faisant un sudo (sachant qu'un sudo sans option ne source ni .profile ni .bashrc etc.) il faut faire :

alias sudo='sudo '

L'utilisateur qui répond brillamment cite la doc de bash :

Aliases allow a string to be substituted for a word when it is used as the first word of a simple command. The shell maintains a list of aliases that may be set and unset with the alias and unalias builtin commands.

The first word of each simple command, if unquoted, is checked to see if it has an alias. If so, that word is replaced by the text of the alias. The characters ‘/’, ‘$’, ‘`’, ‘=’ and any of the shell metacharacters or quoting characters listed above may not appear in an alias name. The replacement text may contain any valid shell input, including shell metacharacters. The first word of the replacement text is tested for aliases, but a word that is identical to an alias being expanded is not expanded a second time. This means that one may alias ls to "ls -F", for instance, and Bash does not try to recursively expand the replacement text. If the last character of the alias value is a space or tab character, then the next command word following the alias is also checked for alias expansion.

Et pourquoi je découvre ça que maintenant moi :rage: ? Quel délire.

P.S : j'ai du lire 100 fois l'immense man bash et j'ai l'impression que j'ai tout à apprendre encore. L'outil est juste incroyablement bien pensé. Trop même.