die(qq/
Usage: vcfutils.pl filter4vcf [options] <in.vcf>
-Options: -d INT min total depth (given DP or DP4) [$opts{D}]
- -D INT max total depth [$opts{d}]
+Options: -d INT min total depth (given DP or DP4) [$opts{d}]
+ -D INT max total depth [$opts{D}]
-q INT min SNP quality [$opts{q}]
-Q INT min RMS mapQ (given MQ) [$opts{Q}]
-1 FLOAT min P-value for strand bias (given PV4) [$opts{1}]