I got "invalid language: C"

[vitaly-zdanevich]

$ wb f 'complex numbers'
invalid language: C

wikibase-cli 18.0.2

Gentoo Linux.

[vitaly-zdanevich]

Solved by

wb config lang en

[maxlath]

Could it be that in your shell environment, $LANG starts with C? That environment variable was checked to infer a preferred language in absence of an explicit config value, but that might lead to pick up invalid languages: I tried to fix that it in 7bbfb11, published in v18.0.3