Tools for just generating a file including all shared variants in all VCF files

Question

[zengtony743]

Hello, I have 4 VCF files which represent variants files from 4 different samples.

1. I do not want to merge them because it takes a lot of time and computer resources.
2. I want to generate a separated VCF format file which has all shared variants by comparing all samples

Thank you!

[GenoMax]

Obtain one vcf file of shared SNPs from input files with different samples using vcf-isec (vcftools)
Identifying private and shared SNPs using VCFtools