第三周作业

1、列出当前系统上所有已经登录的用户的用户名，注意：同一用户登录多次，则只显示一次即可。

[root@localhost ~]# who
root     tty1         2016-08-17 15:29 (:0)
root     pts/0        2016-08-18 22:07 (:0.0)
root     pts/2        2016-08-17 21:41 (:0.0)
[root@localhost ~]# who | cut -d -f1
cut: the delimiter must be a single character
Try `cut --help' for more information.
[root@localhost ~]# who | cut -d' ' -f1
root
root
root
[root@localhost ~]# who | cut -d' ' -f1|uniq
root

2、取出最后登录到当前系统的用户的相关信息。

[root@localhost ~]# who
root     tty1         2016-08-17 15:29 (:0)
root     pts/0        2016-08-18 22:07 (:0.0)
root     pts/2        2016-08-17 21:41 (:0.0)
[root@localhost ~]# who |tail -n 1
root     pts/2        2016-08-17 21:41 (:0.0)
[root@localhost ~]# who |tail -n 1|cut -d' ' -f1
root
[root@localhost ~]# who |tail -n 1|cut -d' ' -f1|id
uid=0(root) gid=0(root) groups=0(root) context=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023

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@localhost ~]# cut -d: -f7 /etc/passwd|uniq -c|sort -n
      1 /bin/bash
      1 /bin/sync
      1 /sbin/halt
      1 /sbin/shutdown
      2 /bin/bash
      4 /sbin/nologin
     22 /sbin/nologin
[root@localhost ~]# cut -d: -f7 /etc/passwd|uniq -c|sort -n|tail -n 1
     22 /sbin/nologin


4、将/etc/passwd中的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到/tmp/maxusers.txt文件中。

[root@localhost ~]# cat /etc/passwd|sort -n -k 3 -t: |tail -n 10|tr 'a-z' 'A-Z'
PULSE:X:497:496:PULSEAUDIO SYSTEM DAEMON:/VAR/RUN/PULSE:/SBIN/NOLOGIN
SASLAUTH:X:498:76:SASLAUTHD USER:/VAR/EMPTY/SASLAUTH:/SBIN/NOLOGIN
RTKIT:X:499:499:REALTIMEKIT:/PROC:/SBIN/NOLOGIN
DINGPENGCHAO:X:500:500:LINUX1:/HOME/DINGPENGCHAO:/BIN/BASH
USER7:X:501:502::/HOME/USER7:/BIN/BASH
MADRIVA:X:1005:2016::/HOME/MADRIVA:/BIN/BASH
MAGEIA:X:1100:1100::/HOME/LINUX:/BIN/BASH
SLACKWARE:X:2002:2016::/HOME/SLACKWARE:/BIN/TCSH
OPENSTACK:X:3003:3005::/HOME/OPENSTACK:/BIN/BASH
MYSQL:X:3004:3007::/HOME/MYSQL:/SBIN/NOLOGIN
[root@localhost ~]# cat /etc/passwd|sort -n -k 3 -t: |tail -n 10|tr 'a-z' 'A-Z' >>/tmp/maxusers.txt

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@localhost ~]# ip add list
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:0c:29:cb:67:a9 brd ff:ff:ff:ff:ff:ff
    inet 192.168.5.135/24 brd 192.168.5.255 scope global eth0
    inet6 fe80::20c:29ff:fecb:67a9/64 scope link
       valid_lft forever preferred_lft forever
3: pan0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN
    link/ether 0e:8d:65:c3:3a:2d brd ff:ff:ff:ff:ff:ff
[root@localhost ~]# ip add list|cut -d " " -f6|sort -n -t -k1
sort: multi-character tab `-k1'
[root@localhost ~]# ip add list|cut -d " " -f6|sort -n -t. -k1


00:00:00:00:00:00
00:0c:29:cb:67:a9
0e:8d:65:c3:3a:2d
::1/128
fe80::20c:29ff:fecb:67a9/64
qdisc
qdisc
qdisc
127.0.0.1/8
192.168.5.135/24
[root@localhost ~]# ip add list|cut -d " " -f6|sort -n -t. -k1|tail -n 1
192.168.5.135/24
[root@localhost ~]# ip add list|cut -d " " -f6|sort -n -t. -k1|tail -n 1|cut -d/ -f1
192.168.5.135


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

[root@localhost ~]# mkdir /tmp/etc
[root@localhost ~]# find /etc/*.conf|tr 'a-z' 'A-Z'|cut -d/ -f3 >>/tmp/etc/conf
[root@localhost ~]# more /tmp/etc/conf
ASOUND.CONF
DNSMASQ.CONF
DRACUT.CONF
FPRINTD.CONF
GAI.CONF
GRUB.CONF
HOST.CONF
INIT.CONF
KDUMP.CONF
KRB5.CONF
LD.SO.CONF
LIBAUDIT.CONF
LIBUSER.CONF
LOGROTATE.CONF
MKE2FS.CONF
MTOOLS.CONF
NSSWITCH.CONF
NTP.CONF
PBM2PPA.CONF
PM-UTILS-HD-APM-RESTORE.CONF
PNM2PPA.CONF
PRELINK.CONF
READAHEAD.CONF
--More--(66%)

7、显示/var目录下一级子目录或文件的总个数。

[root@localhost ~]# ls /var |wc -l
20


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@localhost ~]# cat /etc/group|sort -n -t: -k3|head -n 10
root:x:0:
bin:x:1:bin,daemon
daemon:x:2:bin,daemon
sys:x:3:bin,adm
adm:x:4:adm,daemon
tty:x:5:
disk:x:6:
lp:x:7:daemon
mem:x:8:
kmem:x:9:
[root@localhost ~]# cat /etc/group|sort -n -t: -k3|head -n 10|cut -d: -f1
root
bin
daemon
sys
adm
tty
disk
lp
mem
kmem

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@localhost ~]# cat /etc/fstab /etc/issue >>/tmp/etc/test
[root@localhost ~]# more /tmp/etc/test

#
# /etc/fstab
# Created by anaconda on Sat Jul 30 02:29:43 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
#
UUID=98504afb-f211-4129-9a07-675cffc866b0 /                       ext4    defaul
ts        1 1
UUID=8025043e-c31e-4428-99a6-b2aadc24636b /boot                   ext4    defaul
ts        1 2
UUID=3fa03c86-8307-40c4-9899-de055f0a6855 swap                    swap    defaul
ts        0 0
tmpfs                   /dev/shm                tmpfs   defaults        0 0
devpts                  /dev/pts                devpts  gid=5,mode=620  0 0
sysfs                   /sys                    sysfs   defaults        0 0
proc                    /proc                   proc    defaults        0 0
CentOS release 6.8 (Final)
Kernel \r on an \m


10、
（1）创建组distro,其GID为2016

        [root@localhost ~]# groupadd distro -g 2016

（2）创建用户mandriva,其ID号为1005；基本组为distro;

        [root@localhost ~]# useradd madriva -u 1005 -g distro

（3）创建用户mageia,其ID号为1100，家目录为/home/linux;

        [root@localhost ~]# useradd mageia -u 1100 -d /home/linux

（4）给用户mageia添加密码，密码为mageedu;

        [root@localhost ~]# echo "mageedu"|passwd --stdin mageia
        Changing password for user mageia.
        passwd: all authentication tokens updated successfully.

（5）删除mandriva,但保留其家目录；

        [root@localhost ~]# userdel mandriva

（6）创建用户slackware,其ID号为2002，基本组为distro,附加组peguin;

        [root@localhost ~]# useradd slackware -u 2002 -g distro -G peguin

（7）修改slackware的默认shell为/bin/tcsh;

        [root@localhost ~]# usermod slackware -s /bin/tcsh

（8）为用户slackware新增附加组admins

        [root@localhost ~]# usermod slackware -G admins

（9）为slackware添加密码，且要求密码最短使用期限为3天，最长为180天，警告为3天；

        [root@localhost ~]# echo "123456" |passwd --stdin slackware && chage -w 3 -E 180 -I 3 slackware
Changing password for user slackware.
passwd: all authentication tokens updated successfully.
chage: invalid option -- 'w'
Usage: chage [options] LOGIN

Options:
  -d, --lastday LAST_DAY        set date of last password change to LAST_DAY
  -E, --expiredate EXPIRE_DATE  set account expiration date to EXPIRE_DATE
  -h, --help                    display this help message and exit
  -I, --inactive INACTIVE       set password inactive after expiration
                                to INACTIVE
  -l, --list                    show account aging information
  -m, --mindays MIN_DAYS        set minimum number of days before password
                                change to MIN_DAYS
  -M, --maxdays MAX_DAYS        set maximim number of days before password
                                change to MAX_DAYS
  -R, --root CHROOT_DIR         directory to chroot into
  -W, --warndays WARN_DAYS      set expiration warning days to WARN_DAYS

[root@localhost ~]# chage -l slackware
Last password change                    : Aug 18, 2016
Password expires                    : never
Password inactive                    : never
Account expires                        : never
Minimum number of days between password change        : 0
Maximum number of days between password change        : 99999
Number of days of warning before password expires    : 7


（10）添加用户openstack,其ID号为3003，基本组为clouds,附加组为peguin和nova

        [root@localhost ~]# useradd openstack -u 3003 -g clouds -G peguin,nova

（11）添加系统用户mysql,要求其shell为/sbin/nologin

        [root@localhost ~]# useradd mysql -s /sbin/nologin

（12）使用echo命令，非交互式为openstack添加密码

        [root@localhost ~]# echo "openstack"|passwd --stdin openstack
          Changing password for user openstack.
          passwd: all authentication tokens updated successfully.