单项选择题
A.12345 B.16 C.111111 D.123456
A.filter B.nat C.mangle D.raw
A.grep“^$”/etc/httpd/conf/httpd.conf B.sed-i“/^$/d”/etc/httpd/conf/httpd.conf C.awk-i“/^$/d”/etc/httpd/conf/httpd.conf D.cut“/^$/d”/etc/httpd/conf/httpd.conf