A.usermod-s/sbin/nologinsync
B.usermod-L/sbin/nologinsync
C.编辑/etc/passwd文件,直接将sync用户的登录shell修改为/sbin/nologin
D.passwd–lsync
A.~/.bash_login-->~/.profile-->~/.bash_profile-->/etc/profile
B.~/.bash_profile-->/etc/profile-->~/.profile-->~/.bash_login
C./etc/profile-->~/.bash_profile-->~/.profile-->~/.bash_login
D./etc/profile-->~/.bash_profile-->~/.bash_login-->~/.profile
A.tar-cvfroot.tar.gz/root
B.tar-zcvfroot.tar.gz/root
C.tar-zcvf/rootroot.tar.gz
D.tar-zvfroot.tar.gz/roo
A.echo0>/proc/sys/net/ipv4/icmp_echo_ignore_all
B.echo0>/proc/sys/net/ipv4/tcp_syncookies
C.echo1>/proc/sys/net/ipv4/icmp_echo_ignore_all
D.echo1>/proc/sys/net/ipv4/tcp_syncookies