yum ---> package manager
is a software package based on the RPM manager
can automatically download from the specified server RPM package and the mounting
can handle dependencies between software, one-time installation of all packages dependingyum yum source into a local source to the network source yum
yum
clean all ---> Clear the cache yum original
repolist ---> list the warehouse information
install software ---> install the
update ---> update (update a single software)
List Software ---> View software
list all - -> View all software
list installed ---> list the installed software
list available ---> list the installable software
reinstall software ---> reinstall
remove software ---> uninstall
info software ---> View software information
search software ---> Find software based on information software
whatprovides file ---> to find software that contains the file based on the file
groups list ---> list the software group
groups info ---> to view information about the software group's
groups install sfgroup ---> install software group
groups remove sfgroup ---> uninstall software group (only uninstall the software, do not uninstall dependent)
Note ---> yum use the command must be set up after the success of the yum source to function properly
Experiment specific operation
to install the software dhcp 
reinstall dhcp software 
update software dhcp 
delete dhcp software
View software dhcp 
View all software and filtering software lftp
Yum remove the original source cache 
list information repository (yum source warehouse)
List installed software 
list can install software 
to view dhcp software information 
software information to find relevant software 
software to find this file based on the file that contains lftp 
listed software group 
View base software group
Installing the software group base 
uninstall the software base
.
Local configuration yum source
1. Obtain a mirrored version of the system consistent with the present system
Local rhel7.3 download mirror 
Note ---> rhel7.3 must download rhel7.3 Mirror
2. Mount the mirror 
mounted successfully
3. Set a permanent mount
vim /etc/rc.d/rc.local 
edit mounting information
chmod 755 /etc/rc.d/rc.local ---> this script will be executed automatically at system boot
4. The setting system installation source point
vim /etc/yum.repos.d/rhel7.3.repo> file name must end repo 
Note ---> only have one default file in the directory take effect /etc/yum.repos.d/
[rhel7.3] ---> warehouse name
name = rhel7.3 ---> description of the software source
baseurl = file: ///rhel7.3---> Local Installation Source
gpgcheck = 0 ---> no detection gpgkey
Empty yum source cache 
show has yum source confirms successful configuration 
test:
enter the address in your browser:
Sign-in address test was successful 
.
Shared source of deploying yum (http network share)
Httpd service must be turned on
1. httpd turn 
off the firewall and disabling boot
2. The mount of 
injection ---> httpd have default shared directory / var / www / html / 
set permanently mounted
vim /etc/rc.d/rc.local
Mount edit information
chmod 755 /etc/rc.d/rc.local ---> this script will be executed automatically at system boot
3. Set the system installation source point
vim /etc/yum.repos.d/rhel7.3.repo> file name must end with repo
4. Test:
Enter the address in your browser:
login address the test is successful
http://172.25.254.31/rhel7.3 ---> This address is the network address of the source yum 
install dhcp 
no dependencies prompt, one-time installation