17.1.4 Source List of Package Repository
The place to specify where the package manager should download information about the package is called the source list. The APT tool in Debian determines the source list to download the package from “/etc/apt/sources.list” file. CD-ROM, HTTP server, FTP server, and hard disk can all be sources.
17.1.5 Naming Rules for Package
The package usually has a filename in the form of a “deb” extension. “deb” is an extension to the Debian software package format, which is used for binary packages. The basic format of package file name is as follows.
17.1 Package Manager System
17.1.1 Package
Package is a set of files in which all the necessary data is organized in a predefined way so that the program can be distributed and installed in the manner required by the system. The package contains the metadata needed to apply the program as well as the computer program. Package metadata also has the information about a description and version of the package, and dependencies with other packages (relationship with other packages that must be installed first) together.
Chapter 17 Program Installation & Upgrade
Chapter’s Main Topics
This chapter describes the procedure for installing additional programs in the Raspberry Pi system. It also explains how to remove or upgrade previously installed programs.
It includes descriptions on the following topics:
■ Package manager system
■ Package management tool
■ Obtaining installer program source
■ Installing and reinstall program
■ Uninstalling program
■ Update and upgrade of program
■ Upgrade system kernel and firmware
16.2.3 Creating Text File
There are many ways to create a text file in Raspberry Pi. There is a method to create it from the Shell Terminal, and a method to process it from the Desktop window.
There are several ways to create simple text files from the Shell Terminal as shown below:
16.2.2 Renaming Directory and File
16.2.2.1 “mv” Command – Rename File
To change the name of a directory or file in Shell, you can use the following command.
16.2 Management of Directory and File
16.2.1 Creating Directory
In the Raspberry Pi system, all data is stored in a directory, so the directory must be created before saving the data.
16.1.4 Special Directory and Special File
16.1.4.1 Hidden File
On Linux, directory or files that begin with a “.” are considered hidden. These files are usually configuration files and temporary files that are created by various applications for various purposes. These are managed by assigning a hidden attribute in order to distinguish it from ordinary data and not to be seen in daily routine work.
16.1.3 Specifying Paths for Directory and File
There are two ways to specify the path to a directory or file in Linux, depending on the start position described when specifying the path. One is an absolute path method starting from “/” (root directory), and another one is a relative path method based on the current working position.
16.1.2 Naming Rules for Directory and File
When naming directory and file, the rules below should be followed:
■ It is case sensitive, and lowercase is recommended by default
■ It is recommended to use only alphanumeric characters, hyphen (-), and period (.).
■ It is not recommended to use *, &, |, ” “, $, blank, and so on.