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
A.filter
B.nat
C.mangle
D.raw
A.[-xfile]
B.[-ffile]
C.[-rfile]
D.[-wfile]