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????1.????/etc/skel???/home/tuser1?????/home/tuser1??????????????????????????????κη???????
????[root@localhost ~]# cp -r /etc/skel /home/tuser1 |chmod -R g-rwx??o-rwx /home/tuser1
????2.??/etc/group??????????hadoop
????vim /etc/group  ??? hadoop:x??4015     ??wq   ???????
????3.?????/etc/passwd?????????У???????hadoop?????????ID?hadoop???id?????????/home/hadoop??
????[root@localhost ~]# echo "hadoop:x:4015:4015::/home/hadoop/:/bin/bash" >> /etc/passwd
????4.????/etc/skel???/home/hadoop????????hadoop????????????????????κη??????;
????[root@localhost ~]# cp -r /etc/skel/ /home/hadoop | chmod -R  g-rwx??o-rwx  /home/hadoop
????5.???/home/hadoop???????????????????????hadoop;
????[root@localhost ~]# chown -R hadoop:hadoop /home/hadoop/
????6.???/proc/meminfo????????д??СдS??????У???????????
????[root@localhost ~]# grep "^[sS]" /proc/meminfo
????[root@localhost ~]# grep -i "^s" /proc/meminfo
????7.???/etc/passwd????????shell???/sbin/nologin???????
????[root@localhost ~]# cat /etc/passwd | grep -E -v ".*nologin$"
????8.???/etc/passwd??????????shell?/bin/bash?????
????[root@localhost ~]# grep "/bin/bash$" /etc/passwd | cut -d: -f1
????9.???/etc/passwd????е??λ??????λ??
????[root@localhost ~]# grep  "<[0-9]{1??2}>"  /etc/passwd
????10.???/boot/grub2/grub.cfg????????????????????????
????[root@localhost grub2]# grep "^[[:space:]]+" /boot/grub2/grub.cfg
????11.???/etc/rc.d/rc.local???????#????????????????????????? ???????????????????????
????[root@localhost rc.d]# grep "^#[[:space:]]+[^[:space:]]+" /etc/rc.d/rc.local
????12.???netstat -tan??????н??????'LISTEN'??????????????β????
????[root@localhost rc.d]# netstat -tan | grep "LISTEN[[:space:]]+$"
????13.??????bash??testbash??basher??nologin(??????????shell?/bin/nologin)?? ????????????????????????shell?????????????
????[root@localhost ~]# useradd bash
????[root@localhost ~]# useradd testbash
????[root@localhost ~]# useradd basher
????[root@localhost ~]# useradd -s /bin/nologin nologin
????[root@localhost ~]# grep "^([a-z]*>).*1$" /etc/passwd