#mkdir /data #ls -ld /data #cd / #touch hequan.txt #vi/vim #cat hequan.txt
#echo "hequan" >> hequan.txt #cat >> xx << EOF #cp -a hequan.txt /tmp #mv /data /root #rm -f xx
#rmdir /data #rm -rf /data
#head -2 xxx #tail -2 xxx #grep -v 不显示的 xxx
#sed -n /he/p xxx #sed /hequan/d xxx
#awk /[^hequan]/ xxx
#mkdir -p /xx/xxx #tree xx #man mkdir #mkdir --help #\cp /tmp/xx /xxx #which cp #alias 1=xx #unalias #cat ~/.bashrc
#find / -type f -name "cat" -exec ls -l {} \ | xargs rm -f
#find / -type f +mtime +5 #head -30 xxx | tail -10
#seq 100 xx # seq -s "" 5 #tac #set nu # sed -n 20,30p xxx
# awk '{if(NR>19&&NR<31) print$0}' xxx
#awk -F ":" '{print $1}' /etc/passwd sed -i s#hequan#quanhe#g he
# find / -type f -name he | xargs sed -i s#hequan#quanhe#g he find / -type f -name he | xargs cat
#echo {a..z}
#history # uname -a/-r # cat /etc/centos-release
#diff a b #vimdiff a b
#grep -v不显示 -E连续的字符串 -i不区分大小写
# echo 123456 | passwd --stdin hequan
# history -c #su - root #whoami
#rpm -ivh
# netstat -an
#su - root 切换到root #sudo su - 普通用户拥有ROOT权限
#visudo hequan ALL=(ALL) /usr/sbin/useradd
$ sudo useradd xx
hequan ALL=(ALL) NOPASSWD:ALL
# vi /etc/profile
#echo 'PATH=/hequan:$PATH' >> /etc/profile
#netstat 查看网络状态 -lntup -an
# netstat -lntup |grep ssh # lsof -i:22
# echo {1..6}
half init 0
reboot
shutdown -r now -h now
