N25 week 3 blog

本周的blog开始使用了代码语言格式，我原本以为自然的才是最好的，

orginal的才是最美的，

但是我错了。。。

我发现同学们都在各种markdown，各种排版。我说过我早已过了care这些的年纪，但是我不能脱离群体单独存在，所以我底下了傲娇的头。

本周开始blog标题改为英文，逼格满满，麦满分~

下面开始第$wk_num周的作业

[root@dhcp-10-129-6-166 ~]# wk_num=$[$(date -d 2016-12-12 +%U) - $(date -d 2016-11-21 +%U)]

列出当前系统上所有已经登录的用户的用户名，注意：同一个用户登录多次，则只显示一次即可

[root@dhcp-10-129-6-166 ~]# w -s -h | cut -f 1 -d ' ' | sort -u
root
slackwar
[root@dhcp-10-129-6-166 ~]#

2. 取出最后登录到当前系统的用户的相关信息

[root@dhcp-10-129-6-166 ~]# w
11:53:04 up 6 days, 19:01, 4 users, load average: 0.00, 0.01, 0.05
USER TTY FROM LOGIN@ IDLE JCPU PCPU WHAT
slackwar pts/0 cnbjsl-jm0jtz1.d 10:41 0.00s 0.13s 0.09s sshd: slackware
root pts/1 cnbjsl-jm0jtz1.d 11:19 13:28 0.03s 0.03s -bash
slackwar pts/2 cnbjsl-jm0jtz1.d 11:22 30:38 0.01s 0.01s -bash
openstac pts/3 cnbjsl-jm0jtz1.d 11:53 3.00s 0.00s 0.00s -bash
[root@dhcp-10-129-6-166 ~]# w | tail -1
openstac pts/3 cnbjsl-jm0jtz1.d 11:53 14.00s 0.00s 0.00s -bash

3. 取出当前系统上被用户当作其默认shell的最多的那个shell

[root@dhcp-10-129-6-166 ~]# cat /etc/passwd | cut -f 7 -d : | uniq -c
1 /bin/bash
4 /sbin/nologin
1 /bin/sync
1 /sbin/shutdown
1 /sbin/halt
13 /sbin/nologin
3 /bin/bash
1 /bin/nologin
[root@dhcp-10-129-6-166 ~]# cat /etc/passwd | cut -f 7 -d : | uniq -c | sort
1 /bin/bash
1 /bin/nologin
1 /bin/sync
1 /sbin/halt
1 /sbin/shutdown
3 /bin/bash
4 /sbin/nologin
13 /sbin/nologin
[root@dhcp-10-129-6-166 ~]# cat /etc/passwd | cut -f 7 -d : | uniq -c | sort | tail -1
13 /sbin/nologin
[root@dhcp-10-129-6-166 ~]# cat /etc/passwd | cut -f 7 -d : | uniq -c | sort | tail -1 | tr -s ' ' | cut -f 3 -d ' '
/sbin/nologin
[root@dhcp-10-129-6-166 ~]#

4. 将/etc/passwd中第三个字段数值最大的后10个用户的信息全部改为大写后保存至/tmp/maxusers.txt文件中

[root@dhcp-10-129-6-166 ~]# touch /tmp/maxusers.txt
[root@dhcp-10-129-6-166 ~]# cat /etc/passwd | cut -f 3 -d : | sort -n | tail | tee /tmp/maxusers.txt
89
99
170
996
997
998
999
1100
2002
2003
[root@dhcp-10-129-6-166 ~]# cat /tmp/maxusers.txt
89
99
170
996
997
998
999
1100
2002
2003
[root@dhcp-10-129-6-166 ~]#

5. 取出当前主机的IP地址，提示：对ifconfig命令的结果进行切分

[root@dhcp-10-129-6-166 ~]# ifconfig | tr -s ' ' | cut -f 3 -d ' ' | head -2 | tail -1
10.129.6.166
[root@dhcp-10-12

6. 列出/etc目录下所有以.conf结尾的文件的文件名，并将其名字转换为大写后保存至/tmp/etc.conf文件中

[root@dhcp-10-129-6-166 ~]# ls /etc/*.conf | tr [a-z] [A-Z] >> /tmp/etc.
etc.conf etc.test
[root@dhcp-10-129-6-166 ~]# ls /etc/*.conf | tr [a-z] [A-Z] >> /tmp/etc.conf
[root@dhcp-10-129-6-166 ~]# ls /etc/*.conf
/etc/asound.conf /etc/krb5.conf /etc/man_db.conf /etc/sudo-ldap.conf
/etc/dnsmasq.conf /etc/ld.so.conf /etc/mke2fs.conf /etc/sudo.conf
/etc/dracut.conf /etc/libaudit.conf /etc/nsswitch.conf /etc/sysctl.conf
/etc/e2fsck.conf /etc/libuser.conf /etc/resolv.conf /etc/tcsd.conf
/etc/host.conf /etc/locale.conf /etc/rsyslog.conf /etc/vconsole.conf
/etc/kdump.conf /etc/logrotate.conf /etc/sestatus.conf /etc/yum.conf
[root@dhcp-10-129-6-166 ~]# cat /tmp/etc.conf
/ETC/ASOUND.CONF
/ETC/DNSMASQ.CONF
/ETC/DRACUT.CONF
/ETC/E2FSCK.CONF
/ETC/HOST.CONF
/ETC/KDUMP.CONF
/ETC/KRB5.CONF
/ETC/LD.SO.CONF
/ETC/LIBAUDIT.CONF
/ETC/LIBUSER.CONF
/ETC/LOCALE.CONF
/ETC/LOGROTATE.CONF
/ETC/MAN_DB.CONF
/ETC/MKE2FS.CONF
/ETC/NSSWITCH.CONF
/ETC/RESOLV.CONF
/ETC/RSYSLOG.CONF
/ETC/SESTATUS.CONF
/ETC/SUDO-LDAP.CONF
/ETC/SUDO.CONF
/ETC/SYSCTL.CONF
/ETC/TCSD.CONF
/ETC/VCONSOLE.CONF
/ETC/YUM.CONF
[root@dhcp-10-129-6-166 ~]#

7. 显示/var目录下一级子目录或文件的总个数

[root@dhcp-10-129-6-166 ~]# ll -a /var | wc -l
42
[root@dhcp-10-129-6-166 ~]#

8. 取出/etc/group文件中第三个字段数值最小的10个组的名字

[root@dhcp-10-129-6-166 ~]# cat /etc/passwd | sort -n -k 3 -t : | cut -f 1 -d : | head
root
bin
daemon
adm
lp
sync
shutdown
halt
mail
operator
[root@dhcp-10-129-6-166 ~]#

9. 将/etc/fstab和/etc/issue文件的内容合并为同一个内容后保存至/tmp/etc.test文件中

[root@dhcp-10-129-6-166 ~]# touch /tmp/etc.test
[root@dhcp-10-129-6-166 ~]# cat -s /etc/{fstab,issue} >> /tmp/etc.test
[root@dhcp-10-129-6-166 ~]# cat /tmp/etc.test
#
# /etc/fstab
# Created by anaconda on Thu Dec 1 21:51:31 2016
#
# Accessible filesystems, by reference, are maintained under '/dev/disk'
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#
/dev/mapper/centos-root / xfs defaults 0 0
UUID=6f4ecd86-4eea-468b-81ba-2f3e7b3a59c4 /boot xfs defaults 0 0
/dev/mapper/centos-swap swap swap defaults 0 0
\S
Kernel \r on an \m

10. 请总结描述用户和组管理类命令的使用方法并完成以下练习：

a.创建组distro,其GIDwei 2016

[root@dhcp-10-129-6-166 ~]# groupadd distro -g 2016
[root@dhcp-10-129-6-166 ~]# tail -1 /etc/group
distro:x:2016:

b.创建用户mandriva，其UID为1005，基本组为distro.

[root@dhcp-10-129-6-166 ~]# useradd mandriva -u 1005 -g distro
[root@dhcp-10-129-6-166 ~]# tail1 -1 /etc/passwd
-bash: tail1: 未找到命令
[root@dhcp-10-129-6-166 ~]# tail -1 /etc/passwd
mandriva:x:1005:2016::/home/mandriva:/bin/bash

c.创建用户megeia, 其UID为1100，家目录为/home/linux

[root@dhcp-10-129-6-166 ~]# mkdir /home/linux
[root@dhcp-10-129-6-166 ~]# ll /home
total 0
drwxr-xr-x. 2 root root 6 Dec 19 09:57 linux
drwx------. 2 mandriva distro 59 Dec 19 09:55 mandriva
drwx------. 2 slackware slackware 59 Dec 2 00:41 slackware
[root@dhcp-10-129-6-166 ~]# useradd mageia -u 1100 -d /home/linux
useradd: warning: the home directory already exists.
Not copying any file from skel directory into it.
[root@dhcp-10-129-6-166 ~]# !t
ail -1 /etc/passwd
mageia:x:1100:1100::/home/linux:/bin/bash
[root@dhcp-10-129-6-166 ~]# man chown
man: can't set the locale; make sure $LC_* and $LANG are correct
[root@dhcp-10-129-6-166 ~]# chown mageia:mageia /home/linux
[root@dhcp-10-129-6-166 ~]# ll /home
total 0
drwxr-xr-x. 2 mageia mageia 6 Dec 19 09:57 linux
drwx------. 2 mandriva distro 59 Dec 19 09:55 mandriva
drwx------. 2 slackware slackware 59 Dec 2 00:41 slackware

d.给用户megeia添加密码，密码为mageedu

[root@dhcp-10-129-6-166 ~]# passwd mageia
Changing password for user mageia.
New password:
BAD PASSWORD: The password is shorter than 8 characters
Retype new password:
passwd: all authentication tokens updated successfully.

e.删除mandriva,但保留其家目录

[root@dhcp-10-129-6-166 ~]# userdel mandriva
[root@dhcp-10-129-6-166 ~]# ll /home
total 0
drwxr-xr-x. 2 mageia mageia 6 Dec 19 09:57 linux
drwx------. 2 1005 distro 59 Dec 19 09:55 mandriva
drwx------. 2 slackware slackware 59 Dec 2 00:41 slackware

f.创建用户slackware,其ID号为2002，基本组为distro, 附加组为peguin

[root@dhcp-10-129-6-166 ~]# useradd slackware -u 2002 -g distro -G peguin
useradd: user 'slackware' already exists
[root@dhcp-10-129-6-166 ~]# userdel -r slackware
[root@dhcp-10-129-6-166 ~]# useradd slackware -u 2002 -g distro -G peguin
[root@dhcp-10-129-6-166 ~]# tail -1 /etc/passwd
slackware:x:2002:2016::/home/slackware:/bin/bash
[root@dhcp-10-129-6-166 ~]# tail /etc/group
dbus:x:81:
polkitd:x:995:
dip:x:40:
tss:x:59:
postdrop:x:90:
postfix:x:89:
sshd:x:74:
distro:x:2016:
mageia:x:1100:
peguin:x:2017:slackware

g.修改slackware的默认shell为/bin/tcsh

[root@dhcp-10-129-6-166 ~]# usermod slackware -s /bin/tcsh
[root@dhcp-10-129-6-166 ~]# cat /etc/passwd | grep slackware
slackware:x:2002:2016::/home/slackware:/bin/tcsh

h.为用户slackware新增附件组admins

[root@dhcp-10-129-6-166 ~]# cat /etc/group | grep admins
[root@dhcp-10-129-6-166 ~]# groupadd admins
[root@dhcp-10-129-6-166 ~]# usermod slackware -G admins
[root@dhcp-10-129-6-166 ~]# tail /etc/group
polkitd:x:995:
dip:x:40:
tss:x:59:
postdrop:x:90:
postfix:x:89:
sshd:x:74:
distro:x:2016:
mageia:x:1100:
peguin:x:2017:
admins:x:2018:slackware
[root@dhcp-10-129-6-166 ~]# ^C

i.为用户slackware添加密码，且要求密码最短使用期限为3天，最长为180天，警告3天

[root@dhcp-10-129-6-166 ~]# passwd slackware -n 3 -x 180 -w 3
Adjusting aging data for user slackware.
passwd: Success
[root@dhcp-10-129-6-166 ~]# cat /etc/shadow | grep slackware
slackware:!!:17154:3:180:3:::
[root@dhcp-10-129-6-166 ~]# ^C

j.添加用户openstack, 其ID号为3003，基本组为clouds, 附加组为peguin和nova

[root@dhcp-10-129-6-166 ~]# useradd openstack -g clouds -G peguin,nova
[root@dhcp-10-129-6-166 ~]# tail /etc/group
tss:x:59:
postdrop:x:90:
postfix:x:89:
sshd:x:74:
distro:x:2016:
mageia:x:1100:
peguin:x:2017:openstack
admins:x:2018:slackware
nova:x:2019:openstack
clouds:x:2020:
[root@dhcp-10-129-6-166 ~]# tail /etc/passwd | grep openstack
openstack:x:2003:2020::/home/openstack:/bin/bash
[root@dhcp-10-129-6-166 ~]#

k.添加系统用户mysql, 要求其shell为/bin/nologin

[root@dhcp-10-129-6-166 ~]# useradd mysql -r -s /bin/nologin
[root@dhcp-10-129-6-166 ~]# cat /etc/passwd | grep mysql
ysql:x:996:994::/home/mysql:/bin/nologin

l.使用echo命令，非交互式为openstack添加密码

[root@dhcp-10-129-6-166 ~]# echo openstack | passwd openstack --stdin
Changing password for user openstack.
passwd: all authentication tokens updated successfully.
[root@dhcp-10-129-6-166 ~]#