RPM package management under Linux

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1. Introduction to software package management

1.1, software package classification

1. Source code package (direct code)
   a. Script installation package (an extra installation interface, but convenient)
2. Binary package (that is, the compiled source code file) (alias RPM package or system default package)

1.2. Source package

Advantages
• Open source, you can directly modify the source code
• Free to choose the required functions
• Compile and install, more stable and efficient
• Easy to uninstall (directly delete the source package installation directory)
Disadvantages
• There are many steps in the installation process, prone to spelling mistakes
• Compilation is too long Longer, the installation time is longer than the binary installation
• Because it is compiled and installed, once an error occurs during the installation process, it is difficult for novices to solve

1.3, RPM package

Advantages of binary packages
• The package management system is simple, and operations such as installation, upgrade, and uninstallation can be realized with only a few commands
• The installation speed is much faster than that of source packages (similar to the time of win)
Disadvantages
• After compiling, you cannot see the source code
• Function selection is not as flexible as source code
• Dependency (some software needs other software support, so only supporting software must be installed)

2. RPM package management - package naming and dependencies

2.1, RPM naming rules

For example package full name:httpd-2.2.15-15.e16.centos.1.i686.rpm

name	illustrate
httpd	package name
2.2.15	Software version
15	Number of software releases
el6.centos	This version is suitable for installation in the two linux versions of el6 and centos
i686	Suitable for our 686 microcomputer platform (hardware platform) noarch- means any hardware platform can be installed
rpm	rpm package extension

2.2. RPM package dependencies

• Tree dependency: a->b->c
install a requires b, install b requires c, if we install c first, then install b, and finally install a. To uninstall, first uninstall a, then uninstall b, and finally uninstall c
• Circular dependency: a->b->c->a
installs software a, b, and c at the same time with commands
• Module dependency: all libraries ending with .so. numbers Dependency
Module dependency query website: www.rpmfind.net

3. RPM package management - installation, upgrade and uninstallation

3.1. Package full name and package name

Full package name : When the package to be operated is a package that is not installed, use the full package name. And pay attention to the path
package name : when operating an installed package, use the package name. is to search the database in /var/lib/rpm

3.2. RPM installation

Grammar :rpm-ivh 包全名

parameter	illustrate
-i(install)	Install
-v(verbose)	show details
-h(hash)	show progress
–nodeps	Does not detect dependencies

The picture above depends on the following two, you need to install the following packages first

3.3. RPM package upgrade

Syntax : rpm -Uvh package full name

parameter	illustrate
-U（upgrade）	upgrade

3.4. Uninstall

Syntax : rpm -e package name

parameter	illustrate
-e (erase)	uninstall
–nodeps	do not check dependencies

4. RPM package management - query

4.1. Check whether it is installed

Command: rpm -q package name

parameter	illustrate
-q	query
-a	all

Command: rpm -qa

parameter	illustrate
-a	all

4.2. Query the detailed information of the software package

Command: rpm qi package name

parameter	illustrate
-i	Querying Software Information (information)
-p	Query the information of uninstalled packages (package) To inquire about uninstalled packages, you need to write the full name of the package

4.3. Query the installation location of the files in the package

Command: rpm -ql package name

parameter	illustrate
-l	list
-p	Query information about uninstalled packages

For example: rpm -qlp zsh-4.3.11-4.el6.centos.2.x86_64.rpmYou can query the desired installation location of uninstalled software

4.4. Query which rpm package the system file belongs to

Command: rpm -qf system file name

parameter	illustrate
-f	Query which software package (file) the system file belongs to

4.5. Query the dependencies of the software package

Command: rpm -qR package name

parameter	illustrate
-R	Query package dependencies (requires)
-p	Query information about uninstalled packages (package)

5. RPM package management - checksum file extraction

5.1, RPM package verification

After packaging, first record the characteristics, and then compare the current file with the original file when necessary, compare any changes, see if I made it, and judge whether the file has been modified. Command: rpm
- V installed package name

parameter	illustrate
-V : Verify the files in the specified RPM package (verify)

S 5 T
As shown in the above picture , the details of the 8 pieces of information in the modified verification content are as follows:

parameter	illustrate
S	Whether the file size has changed
M	Whether the type of the file or the permission (rwx) of the file has been modified
5	Whether the file MD5 checksum has changed (can be seen as whether the file content has been modified)
D	In the device, does the slave code change
L	Has the file path changed?
U	Has the owner (owner) of the file changed
G	Whether the group of the file has changed
T	Whether the modification time of the file has changed

The c in the above picture is the file type

parameter	file type
c	configuration file (config file)
d	General documentation (documentation)
g	'ghost' files (ghost) are rare, that is, the file should not be included in this RPM package
l	Authorization file (license file)
r	Description file (read me)

5.2. Extract files from RPM package

Extract the specified file in a package.
If a file is lost or damaged, just download a file in this package.
For example: rpm2cpio 包全名 | cpio -idv; .indicates the absolute path of the file

Command: cpio options < [file|device]

parameter	illustrate
-i	copy-in mode, restore
-d	Automatically create a new directory when restoring
-v	show restore process