Oui!
De la page man:
${parameter:-word}
Use Default Values. If parameter is unset or null, the expansion of word
is substituted. Otherwise, the value of parameter is substituted.
${parameter:=word}
Assign Default Values. If parameter is unset or null, the expansion of word
is assigned to parameter. The value of parameter is then substituted.
Positional parameters and special parameters may not be assigned to in this way.
${parameter:?word}
Display Error if Null or Unset. If parameter is null or unset, the expansion of word (or a message to
that effect if word is not present) is written to the standard error and the shell, if it is not inter‐
active, exits. Otherwise, the value of parameter is substituted.
${parameter:+word}
Use Alternate Value. If parameter is null or unset, nothing is substituted, otherwise the expansion of
word is substituted.
parfait! exactement ce que je cherchais. Besoin d'utiliser * d'autres * variables à coup sûr. –
Strictement parlant, «exporter» n'est pas nécessaire ici. –