Fastest way to find private SNPs for each sample

Question

[Axzd]

Hello

I have 20 VCF files, each representing a single sample, containing SNPs. I have to know, for each sample, what SNPs are private to this sample. What are the options. So far I am usinb bcftools isec, but I am not sure I use it properly

bcftools isec -p dir -n-1 -c all *.vcf.gz

Is it the correct way to use it?

Thanks