- ソフトはクリスタしかありません。
I'm confused because from my understanding, ありません means "does not have/exist"
- I only have this software. (or I have only this software.)
- I don't have any software but this one.
I know that sentece 2 and 3 have a same meaning in English, and we call 1 an affirmative sentence and 2 a negative sentence.
The given sentece 1 is written in a negative sentence, so you got confused.
If you want to rewrite 1 into an affirmative sentence, it would become like:
4.1 ソフトはクリスタだけがあります。
4.2 ソフトはクリスタだけです。
4.2 is more commonly used than 4.1
You can use 1 and 4.2 safely, and I prefer 1 to 4.2 for the meaning of 2 or 3.
EDIT
To clarify, the line I posted was from another person who commented on the artist's/seller's book announcement post. I edited my original post to reflect this.
OP edited the original post according to my answer, so I'll delete all the following answer.
>The context is an artist announced that he is releasing a book about painting digital backgrounds...
If your explanation is correct, don't you think the following sentence is illogical, because the seller says "I'll buy it"?
>背景とかってどうやって描いてるのかすごく気になってたので絶対買います!
If I read it logically, it may imply by supplementing the omitted part like:
>背景とかってどうやって描いてるのかすごく気になってたので もしあなたが私なら 絶対買います!
I'm very interested about how backgrounds are painted so, if I were you, I'm definitely buying (the book).
The particle しか is always followed by a negative of some sort
Taken together, しか+ない means something like "only; nothing but".
– Chocolate♦ Aug 20 '17 at 13:27