[feature] slop without genome file

[shouldsee]

I would like to extract the centre of bed intervals by hijacking bedtools slop. A genome size file is unnecessary here since there is no way that an interval would go off a chromosome during shrinking. Can we turn off the -g argument in such cases?

cat example.bed | bedtools slop -s -l -0.5 -r -0.5 -pct -i -