$ perl -E 'my @x = ("ade:Y", "Abc:X", "Afg:Z"); say for sort @x'
Abc:X
Afg:Z
ade:Y

$ perl -E 'my @x = ("ade:Y", "Abc:X", "Afg:Z"); say for sort { fc($a) cmp fc($b) } @x'
Abc:X
ade:Y
Afg:Z