Querying and Verifiying software packages


Querying and Verifying software packages :
—————————————-
RPM Command lets you query and verifying package contents.

1) Print a description
2) List Contained files
3) Print Scripts excuted
4) Verify the integrity

Print a Description :
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To print a description of an installed package.

Syn :

rpm -qi package_name

Syn :

rpm -qip package_file_name

Cmd :

rpm -qi gnorpm

Listing Contained Files :
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To list the files contained in an installed package.

Syn :

rpm -ql package_name

Cmd :

rpm -ql gnorpm

Printing Scripts :
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To print the pre-installation and post-installation scripts associated with a package.

Syn :

rpm -qp –scripts package_name

Cmd :

rpm -qp –scripts at-3.1.7-11.i386.rpm

Verifying Package Content :
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RPM maintains a record on each file contained in an installed package.

Syn :

rpm -V package_name

Cmd :

rpm -V gnorpm

Gnorpm :
——
Many desktop linux users prefer a graphical user interface ta a command line user interface.

1) Install Package
2) Upgrade Package
3) Query Package
4) Verify Package
5) Unistall Package

Gnorpm includes an interface to the rpm find command.

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Installing & Deleting Software Packages


Installing & Deleting Software Packages :
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Installing Package :
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To Installing an rpm software package, use the following command with -i option.

package-managers

Syn :

rpm -i package_file_name

Options :
——-
-i –> Install a Package
-v –> Verbose for a nicer display
-h –> Print hash marks as the package archive is unpacked

Where package_file_name specifies the name of the file that contains the package you want to install.

Cmd :

rpm -i gnorpm-0.9-10.i386.rpm
gnome-linuxconf-0.23-1.i386.rpm

Administrators like to include -v & -h Flags causes the command to print status information as its excutes.

Ex :

#rpm -ivh gnorom-0.-10.i386.rpm
Press Enter & Type
gnome-linuxconf-0.23-1.386.rpm
gnorpm
###############
gnome-linuxconf
###############

RPM Arguments :
————-
1) –force
2) –nodeps
3) –replacefiles

Ex :

rpm -i –nodeps gnorpm-0.-10.i386
Press Enter
gnome -linuxconf-0.23-1.i386.rpm

Deleting Packages :
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To Remove an installed package, issue a command

Cmd :

rpm -e package_name

redhat-config-packages

Performing Updates & Fixes :
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RPM makes it easy to install new versions of package. issue a command

Cmd :

rpm -uvh package_file_name

Where package file name is the name of the file containing the new version of the package

Ex :

rpm -Fvh gnorpm-0.9-10.i386.rpm

Identifying Installed Packages :
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RPM the version and build numbers of an installed packages, issue a command

Cmd :

rpm -q package_name

Ex :

gnorpm-0.9-10

The version and build number of each installed package.

Cmd :

rpm -qa

Determining File Ownership :
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RPM to learn which package, owns a particular file, issue a command

Syn :

rpm -qf filename

Cmd :

rpm -qf /etc/initab
initscripts-4.16-1

Software and Package Administration(RPM)


Software and Package Administration :
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RPM (Redhat package Manager) RPM Manager the software installation process by tracking information about installed programs. RPM Package Manager (RPM) (originally Red Hat Package Manager; now a recursive acronym) is a package management system. The name RPM variously refers to the .rpm file format, files in this format, software packaged in such files, and the package manager itself. RPM consists of three Components.

1) Package Files
2) RPM Database
3) RPM Command

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Package Files :
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Package files replace the TAR files used befoe advant of RPM, like TAR files & Package fles contain. The files that must be installed unlike TAR files

1) Name & Version of Package
2) Build date & Build host
3) Decription of package
4) Size & MD5 Checksum
5) Identity of the organisation
6) Package group to which package belongs

Cmd :

Package-Version-Buildarchitecture.rpm

rpm-package-management-300x257

RPM Database :
————
Once a package installed, informtion about the package is stored in the RPM database which resides in /var/lib/rpm.

figure_01

RPM Commands :
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The rpm command is the excutable componet of the RPM facility.

1) Installation Packages
2) Updating Packages
3) Removing Packages
4) Querying RPM Database
5) Querying a Package File
6) Building a Package File
7) Validating a Package
8) Validating Package file

Init Process


Init Process
In Unix-based computer operating systems, init (short for initialization) is the first process started during booting of the computer system. Init is a daemon process that continues running until the system is shut down. The First program that is run under the kernel is init. This program is always processes 1. The linux kernel can be told which program to use as init by passing the init=boot parameter. If this parameter is not specified then the kernel will try to excute ‘/sbin/init’,’/etc/init’,’/bin/init’ & ‘/bin/sh’.

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The init process is identified by process id “1”.
Init is Responsible for starting system processess as defined in the /etc/inittab file.
Init typically will start multiple instances which waits for console logins which spawn ones user shell process.
Upon shutdown, init controls the sequence & Procssess for shutdown.
The first thing the kernl does is to execute init program.
Init is the root of all processes excuting on linux.
The first processes that init starts is a script /etc/rc.d/rc.sysinit
Based on the appropriate run-level, scripts are executed to start various processes to run the system and make it functional.

Kernel Initialization


Kernel Initialization :
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1) The kernel initializes hardware as well as kernel data structures.
2) The kernel command line is saved.
3) Hard-drive information is retrieved from the BIOS.
4) The memory size is determined, again through the BIOS.
5) The hardware is prepared to move to protected mode. (Protected mode is the normal memory mode that the system runs in. It allows for the use of All interupts are disabled).
6) The “Protected Mode Enabled” bit is set in the Machine Status Word. This step actually turns on protected mode.
7) The page tables are initialized. These are part of virtual memory support.
8) Paging is enabled by setting the PG bit in control register 0. This turns on virtual memory.
9) Exception handlers are installed. These routines get control when a programming error is detected by the hardware.
10) The timer interrupt is installed.
11) kernel detects the attached devices in the system & loads thier drivers into RAM.
12) mounts root filesystem into read-only memory mode.
13) then initializes the ‘init’ process for further processing
14) init=it is the first process that is started at the boot time.

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