Linux third time job

1. List the user name of all logged-in users on the current system, note: The same user logged in multiple times, only once.

[email protected] ~]# who | Cut-d '-F 1//Cut string,-D indicates the character is a space,-F, 1th column Jun_shaojun_shaojun_shaojun_shaorootroot[[email protected] ~]# who | Cut-d '-F 1 | Sort-u Jun_shaoroot

2. Remove the information about the user who last logged in to the current system.

[[EMAIL PROTECTED] ~]$ WHO | SORT  -R -K 3JUN_SHAO PTS/5         2016-08-20 01:09  (192.168.0.100) root      pts/4        2016-08-20 00:34  ( 192.168.0.100) root     pts/3         2016-08-20 00:34  (192.168.0.100) jun_shao pts/2         2016-08-20 00:33  (192.168.0.100) jun_shao pts/1         2016-08-20 00:33  (192.168.0.100) jun_shao pts/0         2016-08-20 00:32  (: 0) jun_shao :0            2016-08-20 00:31  (: 0) [[email protected] ~]$ who | sort  -r  -k 3 | head -n 1 jun_shao pts/5        2016-08-20 01:09  ( 192.168.0.100) [[email protected] ~]$ who | sort  -r -k 3 |  head -n 1 > /tmp/last.txt[[email protected] ~]$ cat /tmp/ last.txt jun_shao pts/5        2016-08-20 01:09  ( 192.168.0.100)

3. Remove the shell that is the user's default shell on the current system.

[Email protected] ~]$ cut-d:-F 7/etc/passwd | Sort | uniq-c | Sort-f | Tail-n 1 >/tmp/shell.txt[[email protected] ~]$ cat/tmp/shell.txt 39/sbin/nologin

4, the third field in the/etc/passwd the value of the largest 10 users of the information is changed to uppercase and saved to the/tmp/maxusers.txt file.

[[email protected] ~]$ sort -t : -k 3 -n /etc/passwd |  tail -n 10 | tr [a-z] [a-z] > /tmp/maxusers.txt[[email  Protected] ~]$ cat /tmp/maxusers.txt geoclue:x:992:989:user for geoclue:/var/lib /geoclue:/sbin/nologinlibstoragemgmt:x:993:990:daemon account for libstoragemgmt:/var/run/lsm:/ Sbin/nologinsaslauth:x:994:76:saslauthd user:/run/saslauthd:/sbin/nologincolord:x:995:992:user for  colord:/var/lib/colord:/sbin/nologinunbound:x:996:993:unbound dns resolver:/etc/unbound:/sbin/ nologinpolkitd:x:997:995:user for polkitd:/:/sbin/nologinsystemd-network:x:998:996:systemd  network management:/:/sbin/nologinsystemd-bus-proxy:x:999:997:systemd bus proxy:/:/sbin/ nologinjun_shao:x:1000:1000:jun_shao:/home/jun_shao:/bin/bashnfsnobody:x:65534:65534:anonymous nfs  User:/var/lib/nfs:/sbin/nologin 

5, take out the IP address of the current host, hint: The result of ifconfig command is sliced.

[Email protected] ~]$ Ifconfig eno16777736 | Grep-w "inet" | Cut-d '-F 10192.168.0.101

6. List the file names of all files ending with. conf in/etc directory and convert their names to uppercase and save them to the/tmp/etc.conf file.

[Email protected] jun_shao]# ls/etc/|grep ' \.conf$ ' >/tmp/etc.conf[[email protected] jun_shao]# cat/tmp/etc.conf Asound.confautofs.confautofs_ldap_auth.confbrltty.confcgconfig.confcgrules.confcgsnapshot_ Blacklist.confchrony.confdleyna-server-service.confdnsmasq.confdracut.confe2fsck.conffprintd.conffuse.confhba.confhost.co Nfidmapd.confipsec.confkdump.confkrb5.confksmtuned.confld.so.conflibaudit.conflibuser.conflocale.conflogrotate.confman _db.confmke2fs.confmtools.confnfsmount.confnsswitch.confntp.confnumad.confoddjobd.confpbm2ppa.confpnm2ppa.confradvd.confr Equest-key.confresolv.confrsyncd.confrsyslog.confsestatus.confsos.confsudo.confsudo-ldap.confsysctl.conftcsd.confupdatedb . confusb_modeswitch.confvconsole.confwvdial.conf

7. Displays the total number of sub-directories or files in the/var directory.

[Email protected] ~]$ Ll-a/var/| Wc-l26

8. Remove the names of the 10 groups with the smallest number of the third field in the/etc/group file.

[Email protected] ~]$ Cat/etc/group | Sort-t:-K 3-n-r | Tail-n 10kmem:x:9:mem:x:8:lp:x:7:disk:x:6:tty:x:5:adm:x:4:sys:x:3:daemon:x:2:bin:x:1:root:x:0:

9, the contents of the/etc/fstab and/etc/issue files are merged into the same content and saved to the/tmp/etc.test file.

[[email protected] ~]$ cat /etc/fstab /etc/issue > /tmp/etc.test [[ email protected] ~]$ cat /tmp/etc.test ## /etc/fstab# created by  Anaconda on wed aug 17 16:50:22 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 0UUID=be50a901-277e-4252-b8be-717299df19f5 /boot                    xfs      defaults        0 0/dev/mapper/centos-swap swap                     swap     defaults        0 0\SKernel \r  On an \m

10. Summarize the methods used to describe the user and group management commands and complete the following exercises:

(1), create group distro, its GID is 2016;

[Email protected] jun_shao]# groupadd-g distro

(2), create user Mandriva, whose ID number is 1005; basic group is distro;

[Email protected] jun_shao]# useradd-u 1005-g distro Mandriva

(3), create user Mageia, whose ID number is 1100, home directory is/home/linux;

[Email protected] jun_shao]# useradd-u 1100-d/home/linux Mageia

(4), to the user mageia add password, password for mageedu;

[Email protected] jun_shao]# passwd mageia changing password for user Mageia. New Password:bad password:the password is shorter than 8 characters retype new Password:passwd:all authe Ntication Tokens updated successfully.

(5), delete Mandriva, but retain their home directory;

[Email protected] home]# Userdel Mandriva [[email protected] home]# ls Jun_shao linux m Andriva

(6), create user Slackware, its ID number is 2002, the basic group is distro, additional group Peguin;

[Email protected] home]# groupadd Peguin [[email protected] home]# useradd-u 2002-g distro-g Pegui n Slackware [[email protected] home]# ID slackware uid=2002 (slackware) gid=2016 (distro) groups=2016 (distro) (p Eguin)

(7), modify the Slackware default shell for/BIN/TCSH;

[Email protected] home]# usermod-s/bin/tcsh Slackware

[Email protected] home]# tail-n 1/etc/passwd slackware:x:2002:2016::/home/slackware:/bin/tcsh

(8), add additional Group admins for user Slackware;

[Email protected] jun_shao]# usermod-a-G admins slackware [[email protected] jun_shao]# ID slackware uid=2002 ( Slackware) gid=2016 (distro) groups=2016 (distro), Peguin (2018)

(9), add password for Slackware, and require the minimum password age of 3 days, the maximum is 180 days, warning for 3 days;

[Email protected] jun_shao]# passwd Slackware |     passwd slackware-n 3-x 180-w 3 Adjusting aging data for user Slackware.      passwd:success new Password:bad password:the password is shorter than 7 characters retype New password: [Email protected] jun_shao]# tail-n 1/etc/shadow Slackware:$6$6sp2wfd/$9oyf6m0wbsnb/qvmekcy/qaa494ctedvdwx2jktap Of.. 6ud.ycenkpe3byuwfr20wy6dwdiu6x1fioum6kd20:17033:3:180:3:::

(10), add user OpenStack, whose ID number is 3003, the basic group is clouds, the additional group is Peguin and Nova;

[Email protected] jun_shao]# useradd-u 3003-g clouds-g Peguin,nova openstack [[email protected] Ju n_shao]# ID OpenStack uid=3003 (openstack) gid=2019 (Clouds) groups=2019 (Clouds), Peguin (Nova)

(11), add the system user MySQL, request its shell for/sbin/nologin;

[Email protected] jun_shao]# useradd-r-s/sbin/nologin MySQL [[email protected] jun_shao]# tail-n 1/ETC/PASSWD Mysql:x:987:982::/home/mysql:/sbin/nologin

(12), use the echo command, non-interactive add a password for OpenStack.

[[email protected] jun_shao]# echo "admin" | passwd--stdin OpenStack

This article is from "June's personal blog" blog, please be sure to keep this source http://june1015.blog.51cto.com/4804270/1840705

Linux third time job