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] desktop]# who
Xu Tty5 2016-08-21 23:20
Root tty1 2016-08-21 23:12 (: 0)
Root pts/0 2016-08-21 23:13 (: 0.0)
[Email protected] Desktop]# who | Cut-d '-f1 |sort-u
Root
Xu
2. Remove the information about the user who last logged in to the current system.
[[Email protected] Desktop]# last | Head-1
Xu Tty5 Sun 23:20 still logged in
3. Remove the shell that is the user's default shell on the current system.
[[Email protected] Desktop]# cat/etc/passwd| Cut-d ': '-f7 | uniq-c | Sort-n | Tail-1 | Cut-d '-f7
4, the information of the third field in/ETC/PASSW D with the largest number of the first 10 users is changed to uppercase and then saved to the/tmp/maxusers.txt file.
SORT-T:-k3-n/etc/passwd | tail-10 | TR "A-Z" "A-Z" >/tmp/maxusers.txt
5, take out the IP address of the current host, hint: The result of ifconfig command is sliced.
Ifconfig | grep ' inet addr: ' |cut-d:-f2|cut-d '-f1
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.
ls/etc | grep '. conf$ ' | Tr ' A-Z ' A-Z ' >/tmp/etc.conf
7. Displays the total number of sub-directories or files in the/var directory.
[Email protected] ~]# Ls/var |wc-w
21st
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:-n-k3|head-10|cut-d:-f1
Root
Bin
Daemon
Sys
cd/
Tty
Disk
Lp
Mem
Kmem
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
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;
Groupadd-g distro
(2), create user Mandriva, whose ID number is 1005; basic group is distro;
Useradd-u 1005 mandriva-g distro
(3), create user Mageia, whose ID number is 1100, home directory is/home/linux;
Useradd-u 1100 mageia-d/home/linux Mageia
(4), to the user mageia add password, password for mageedu;
echo "Password" | passwd--stdin Mageia
(5), delete Mandriva, but retain their home directory;
Userdel Mandriva
(6), create user Slackware, its ID number is 2002, the basic group is distro, additional group Peguin;
Useradd-u 2002-g distro-g Peguin Slackware
(7), modify the Slackware default shell for/BIN/TCSH;
Usermod-s/bin/tcsh Slackware
(8), add additional Group admins for user Slackware;
Usermod-g-A admins Slackware
(9), add password for Slackware, and require the minimum password age of 3 days, the maximum is 180 days, warning for 3 days;
(10), add user OpenStack, whose ID number is 3003, the basic group is clouds, the additional group is Peguin and Nova;
Useradd-u 3003-g clouds-g Peguin,nova OpenStack
(11), add the system user MySQL, request its shell for/sbin/nologin;
[[email protected] tmp]# useradd-r-s/sbin/nologin MySQL
(12), use the echo command, non-interactive add a password for OpenStack.
echo "passwd" | passwd--stdin OpenStack
Linux Jobs (iii)