Linux third week 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 '-f1 | Sort | Uniq

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

[email protected] ~]$ who |TAIL-1

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

[Email protected] ~]$ cut-d:-f7/etc/passwd |uniq-c |sort-n |tail-1

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:-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.

[Email protected] yu]# ifconfig |grep inet |head-1

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] ~]$ ls/etc/*.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] ~]$ ll-a/var |wc-l

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:-k3-n-r | Tail-10

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;   

[Email protected] yu]# groupadd-g distro

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

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

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

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

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

[Email protected] yu]# passwd Mageia

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

[Email protected] yu]# Userdel Mandriva

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

[Email protected] yu]# Groupadd Peguin

[Email protected] yu]# useradd-u 2002-g distro-g Peguin Slackware

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

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

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

[Email protected] yu]# groupadd Admins

[Email protected] yu]# usermod-a-G 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;

[Email protected] yu]# passwd Slackware | passwd slackware-n 3-x 180-w 3

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

[Email protected] yu]# Groupadd Nova

[Email protected] yu]# Groupadd clouds

[Email protected] yu]# useradd-u 3003-g clouds-g Peguin,nova OpenStack

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

[Email protected] yu]# useradd mysql-u 499-s/sbin/nologin

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

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

This article from "A Linux Tour" blog, declined reprint!

Linux third week job