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.
Chapter 16 File Management
Chapter’s Main Topics
This chapter explains various methods of managing directorys and data stored in the system. Here we will explain how to handle in the Shell Terminal, and how to handle through the window.
It includes descriptions on the following topics:
■ basic structure of directory and file
■ Management of directory and file
■ Utilization of directory and file
■ Management of text file
16.1 Basic Structure of Directory and File
16.1.1 Concept of Directory and File
16.1.1.1 Folder or Directory
Directory does not have any specific data on its own, but is used to manage files that have specific data. Directory is used to improve the efficiency of use by classifing and storing a large number of files and facilitating searches later.
2.4.2 장치별 전류 소비
Raspberry Pi에서 전체 USB port에 공급할 수 있는 전류에 제한이 있다. Raspberry Pi 1 model A, A+, B는 전체 USB 기기에 최대 500mA 전류를 공급할 수 있다. Raspberry Pi model 1 model B+ 와 Raspberry Pi 2 model B에서는 전체 USB 기기에 최대 전환 가능한 600mA/1.2A 의 전류를 공급할 수 있는데, firmware 설정에 따라 서로 전환이 가능하다. Raspberry Pi 3 model B에서는 USB port에 최대 1.2 Amp까지 전류를 공급할 수 있도록 개선되어 이전 model에 비해서 많은 전류가 필요한 USB 장치를 더 많이 Pi에 직접 연결하여 사용할 수 있게 되었다.
2.4.1 Micro USB power supply port
Raspberry Pi에서는 시스템에 전원을 공급하기 위해서 Micro USB socket를 지원하고 있다. Micro USB socket은 보통 휴대폰이나 모바일 기기에서 충전용으로 많이 사용되는 표준이다.
시스템에 공급되는 전원은 5.1V DC 전원을 사용하고 있다. Raspberry Pi에서 얼마나 많은 전류를 필요로 하는가는 Raspberry Pi의 model과 Raspberry Pi에 연결되어 있는 주변기기의 종류와 개수에 달려 있다.