【填空题】若要查询Linux下是否安装了FTP软件，正确的命令是（）

A.rpm –qa | grep vsftpd

B.rpm -a |grep vsftpd

C.service vsftpd start

D.service ftp start

A.rpm –aq

B.rpm –ed

C.rpm –ui

D.rpm -qi

A.rpm -q firefox

B.rpm -l firefox

C.rpm --list firefox

D.rpm --search firefox

A.rpm -q firefox

B.rpm -l firefox

C.rpm --list firefox

D.rpm --search firefox

A.Y.是

B.N.否

A.rpm –q dhcp

B.rpm –q dhcpd

C.ps –aux | grep bind

D.ps –aux | grep dns