Off topic:How to do batch processing with mpileup in a Linux shell for loop?

Question

[elvissober]

I want to make VCFs on a set of .sams (.bams):

for I in ls (*.sam) # calling variants on .sam files
do
    ./samtools mpileup -R -d | bcftools view -g - > test.vcf $i # what to write here correctly?
done