1、复制/etc/skel目录为/home/tuser1,要求/home/tuser1及内部文件的属组和其它用户均没有任何访问权限。
[root@localhost ~]# install -d -m 600 /etc/skel /home/tuser1
[root@localhost ~]# ls -l /home
drw-------. 2 root root 6 11月 15 20:23 tuser1
2、编辑/etc/group文件，添加组hadoop。
[root@localhost ~]# vim /etc/group
[root@localhost ~]# cat /etc/group
hadoop:x:1002:
3、手动编辑/etc/passwd文件新增一行，添加用户hadoop，其基本组id为hadoop组的id号；其家目录为/home/hadoop.
[root@localhost ~]# vim /etc/passwd
[root@localhost ~]# idhadoop
uid=1002(hadoop) gid=1002(hadoop) 组=1002(hadoop)
[root@localhost ~]# cat /etc/passwd
hadoop:x:1002:1002::/home/hadoop:/bin/bash
4、复制/etc/skel目录为/home/hadoop/,要求修改hadoop目录的属组和其它用户没有任何访问权限。
[root@localhost ~]# install -d -m 600 /etc/skel/ /home/hadoop
[root@localhost ~]# ls -l /home
drw-------. 2 root root 6 11月 15 20:49 hadoop
5、修改/home/hadoop目录及其内部所以文件的属主为hadoop，属组为hadoop。
[root@localhost ~]# install -d -o hadoop -g hadoop /home/hadoop/ /home/hadoop/
[root@localhost ~]# ls -l /home/
drwxr-xr-x. 2 hadoophadoop 6 11月 15 20:49 hadoop
6、显示/proc/meminfo文件中以大写或小写s开头的行，两种方式。
[root@localhost ~]# grep "^[sS]" /proc/meminfo
SwapCached: 0 kB
SwapTotal: 2098172 kB
SwapFree: 2098172 kB
Shmem: 7196 kB
Slab: 93980 kB
SReclaimable: 47692 kB
SUnreclaim: 46288 kB
[root@localhost ~]# grep -i "^s" /proc/meminfo
SwapCached: 0 kB
SwapTotal: 2098172 kB
SwapFree: 2098172 kB
Shmem: 7196 kB
Slab: 93980 kB
SReclaimable: 47692 kB
SUnreclaim: 46288 kB
7、显示/etc/passwd文件中默认shell为非/sbin/nologin的用户。
[root@localhost ~]# grep -o ".*[^/sbin/nologin]" /etc/passwd
root:x:0:0:root:/root:/bin/bash
bin:x:1:1:bin:/bin:
daemon:x:2:2:daemon:/sbin:
adm:x:3:4:adm:/var/adm:
lp:x:4:7:lp:/var/spool/lpd:
sync:x:5:0:sync:/sbin:/bin/sync
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdow
halt:x:7:0:halt:/sbin:/sbin/halt
mail:x:8:12:mail:/var/spool/mail:
operator:x:11:0:operator:/root:
games:x:12:100:games:/usr/games:
ftp:x:14:50:FTP User:/var/ftp:
nobody:x:99:99:Nobody:/:
avahi-autoipd:x:170:170:Avahi IPv4LL Stack:/var/lib/avahi-autoipd:
systemd-bus-proxy:x:999:997:systemd Bus Proxy:/:
systemd-network:x:998:996:systemd Network Management:/:
dbus:x:81:81:System message bus:/:
polkitd:x:997:995:User for polkitd:/:
abrt:x:173:173::/etc/abrt:
colord:x:996:994:User for colord:/var/lib/colord:
libstoragemgmt:x:995:992:daemon account for libstoragemgmt:/var/run/lsm:
setroubleshoot:x:994:991::/var/lib/setroubleshoot:
rpc:x:32:32:Rpcbind Daemon:/var/lib/rpcbind:
rtkit:x:172:172:RealtimeKit:/proc:
chrony:x:993:990::/var/lib/chrony:
tss:x:59:59:Account used by the trousers package to sandbox the tcsd daemon:/dev/null:
geoclue:x:992:989:User for geoclue:/var/lib/geoclue:
usbmuxd:x:113:113:usbmuxd user:/:
ntp:x:38:38::/etc/ntp:
mysql:x:27:27:MariaDB Server:/var/lib/mysql:
rpcuser:x:29:29:RPC Service User:/var/lib/nfs:
nfsnobody:x:65534:65534:Anonymous NFS User:/var/lib/nfs:
sssd:x:991:988:User for sssd:/:
pulse:x:171:171:PulseAudio System Daemon:/var/run/pulse:
gdm:x:42:42::/var/lib/gdm:
postfix:x:89:89::/var/spool/postfix:
sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:
tcpdump:x:72:72::/:
dunwen_jian:x:1000:1000::/home/dunwen_jian:/bin/bash
centos01:x:1001:1001::/home/centos01:/bin/bash
hadoop:x:1002:1002::/home/hadoop:/bin/bash
8、显示/etc/passwd文件中默认shell为/bin/bash的用户。
[root@localhost ~]# grep ".*/bin/bash" /etc/passwd
root:x:0:0:root:/root:/bin/bash
dunwen_jian:x:1000:1000::/home/dunwen_jian:/bin/bash
centos01:x:1001:1001::/home/centos01:/bin/bash
hadoop:x:1002:1002::/home/hadoop:/bin/bash
9、找出/etc/passwd文件中的一位数或两位数。
[root@localhost ~]# grep "\<[0-9]\{1,2\}\>" /etc/passwd
root:x:0:0:root:/root:/bin/bash
bin:x:1:1:bin:/bin:/sbin/nologin
daemon:x:2:2:daemon:/sbin:/sbin/nologin
adm:x:3:4:adm:/var/adm:/sbin/nologin
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
sync:x:5:0:sync:/sbin:/bin/sync
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
halt:x:7:0:halt:/sbin:/sbin/halt
mail:x:8:12:mail:/var/spool/mail:/sbin/nologin
operator:x:11:0:operator:/root:/sbin/nologin
games:x:12:100:games:/usr/games:/sbin/nologin
ftp:x:14:50:FTP User:/var/ftp:/sbin/nologin
nobody:x:99:99:Nobody:/:/sbin/nologin
dbus:x:81:81:System message bus:/:/sbin/nologin
rpc:x:32:32:Rpcbind Daemon:/var/lib/rpcbind:/sbin/nologin
tss:x:59:59:Account used by the trousers package to sandbox the tcsd daemon:/dev/null:/sbin/nologin
ntp:x:38:38::/etc/ntp:/sbin/nologin
mysql:x:27:27:MariaDB Server:/var/lib/mysql:/sbin/nologin
rpcuser:x:29:29:RPC Service User:/var/lib/nfs:/sbin/nologin
gdm:x:42:42::/var/lib/gdm:/sbin/nologin
postfix:x:89:89::/var/spool/postfix:/sbin/nologin
sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin
tcpdump:x:72:72::/:/sbin/nologin
10、显示/boot/grub2/grub.cfg文件中至少一个空白字符开头的行。
[root@localhost ~]# grep "^[[:space:]]\+[[:space:]]" /boot/grub2/grub.cfg
load_env
set default="${next_entry}"
set next_entry=
save_env next_entry
set boot_once=true
set default="${saved_entry}"
menuentry_id_option="--id"
menuentry_id_option=""
set saved_entry="${prev_saved_entry}"
save_env saved_entry
set prev_saved_entry=
save_env prev_saved_entry
set boot_once=true
if [ -z "${boot_once}" ]; then
saved_entry="${chosen}"
save_env saved_entry
fi
if [ x$feature_all_video_module = xy ]; then
insmod all_video
else
insmod efi_gop
insmod efi_uga
insmod ieee1275_fb
insmod vbe
insmod vga
insmod video_bochs
insmod video_cirrus
fi
set timeout_style=menu
set timeout=5
set timeout=5
source ${prefix}/user.cfg
if [ -n ${GRUB2_PASSWORD} ]; then
set superusers="root"
export superusers
password_pbkdf2 root ${GRUB2_PASSWORD}
fi
search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos1 --hint-efi=hd0,msdos1 --hint-baremeta l=ahci0,msdos1 --hint='hd0,msdos1' 0e66967e-71ab-473f-a181-635ec181283c
search --no-floppy --fs-uuid --set=root 0e66967e-71ab-473f-a181-635ec181283c
search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos1 --hint-efi=hd0,msdos1 --hint-baremeta l=ahci0,msdos1 --hint='hd0,msdos1' 0e66967e-71ab-473f-a181-635ec181283c
search --no-floppy --fs-uuid --set=root 0e66967e-71ab-473f-a181-635ec181283c
source ${config_directory}/custom.cfg
source $prefix/custom.cfg;
11、显示/etc/rc.d/rc.local文件中以#开头，后面跟至少一个空白字符，而后又有至少一个非空白字符的行。
[root@localhost ~]# grep "^#[[:space:]]\+[^[:space:]]" /etc/rc.d/rc.local
# THIS FILE IS ADDED FOR COMPATIBILITY PURPOSES
# It is highly advisable to create own systemd services or udev rules
# to run script s during boot instead of using this file.
# In contrast to previous versions due to parallel execution during boot
# this script will NOT be run after all other services.
# Please note that you must run 'chmod +x /etc/rc.d/rc.local' to ensure
# that this script will be executed during boot.
12、打出netstat -tan命令执行结果中以‘LISTEN',后或跟空白字符结尾的行。
[root@localhost ~]# netstat -tan | grep "\<LISTEN[[:space:]]\+"
tcp 0 0 0.0.0.0:53164 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:111 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN
tcp 0 0 127.0.0.1:631 0.0.0.0:* LISTEN
tcp 0 0 127.0.0.1:25 0.0.0.0:* LISTEN
tcp 0 0 :::111 :::* LISTEN
tcp 0 0 :::22 :::* LISTEN
tcp 0 0 ::1:631 :::* LISTEN
tcp 0 0 ::1:25 :::* LISTEN
tcp 0 0 :::34985 :::* LISTEN
13、添加用户bash，testbash，basher，nologin（此一个用户的shell为/sbin/nologin），而后找出当前系统上其用户名和默认shell相同的用户的信息。
[root@localhost ~]# grep -E "^([^:]+\>).*\1$" /etc/passwd
sync:x:5:0:sync:/sbin:/bin/sync
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
halt:x:7:0:halt:/sbin:/sbin/halt
bash:x:4004:4004::/home/bash:/bin/bash
nologin:x:4007:4007::/home/nologin:/sbin/nologin
